A Guide to the Fossils at the Always Welcome Inn, Baker City, Oregon
by Kate Asplund, Eric Bergey, Misty Davis, Brooke Garton, Bryan Grimshaw, Allison Kuenzli, Story Miller, Carli Morris, Kelsey Swanson, Corby Weyhmiller, and Jay Van Tassell
Science Department, Badgley Hall, Eastern Oregon University, One University Boulevard, La Grande, OR 97850, jvantass@eou.edu
Eastern Oregon University student Corby Weyhmiller carefully excavates the humerus of the grison, Trigonictis, from the Always Welcome Inn outcrop.
The slopes behind the Always Welcome Inn contain fossils that hint at what this area was like millions of years ago and what has happened to it since. This guide answers some of the most commonly asked questions about this important fossil locality and describes the fossils that we have found so far.
Please ask for permission before collecting fossils from this site!
Figure 1. Eastern Oregon University student Carli Morris dry sieves fossils at the Always Welcome Inn.
WHO DISCOVERED THE FOSSILS AT THE ALWAYS WELCOME INN AND WHO IS HELPING TO IDENTIFY THEM?
The fossils behind the Always Welcome Inn were discovered in May 2002 by a mollusk expert (malacologist) named Terry Frest. Dr. Frest is a senior partner at Deixus Consultants in Seattle, Washington. After spending the night at the Always Welcome Inn, he decided to explore the outcrop behind the Inn and discovered fossil fish bones, bivalves (clams), gastropods (snails), ostracods (small crustaceans), charophytes (green algae), and diatoms.
Dr. Frest contacted Mark Ferns of the Oregon Department of Geology and Mineral Industries in Baker City and let him know about the fossils. Mark Ferns then contacted Jay Van Tassell, the geology professor at Eastern Oregon University in La Grande. In March 2004, Mark Ferns, Jay Van Tassell, Rob Ledgerwood and Jesse Steele (two of Jay’s students) searched the Always Welcome Inn for additional fossils. Since then, Jay and his students have collected fossils from the site many times. Groups from the University of Michigan, the University of Montana, and Pine-Eagle High School have also helped sample the outcrop (Figs. 1, 2, and 3).
This study would not be possible without the expertise and generous assistance of paleontologists from all across the United States. We are very grateful to Dr. Jerry Smith of the University of Michigan (fish); Dr. Greg McDonald, Dr. Ted Fremd, and Matt Smith of the National Park Service; Dr. Jim Mead of Northern Arizona University (salamanders, frogs, and snakes); Dr. Bob Martin of Murray State University (voles); Dr. Dave Steadman of the Florida Museum of Natural History (birds), and Dr. Terry Frest (gastropods and bivalves) for their help. Dr. William Akersten of the Idaho Museum of Natural History, Dr. Natalia Rybczynski of the Canadian Museum of Nature, Dr. Chris Bell of the University of Texas, and Dr. Rick Zakrzewski of Fort Hays State University have also provided valuable assistance.
Figure 2. Eastern Oregon University student Story Miller shows a group of Pine-Eagle High School students and their teacher, Troy Tubbs, how to search for fossils at the Always Welcome Inn. Note the normal faults in the outcrop behind them.
Figure 3. Pine-Eagle high school student, Adora Brockman, searches for more pieces of the beaver jaw she discovered at the Always Welcome Inn.
WHAT TYPES OF FOSSILS HAVE BEEN FOUND?
The list of fossils found at the Always Welcome Inn now includes diatoms, charophytes, plants, sponges, snails, clams, ostracods, sunfish, minnows, frogs, salamanders, snakes, pond turtles, birds (ducks and rails), rabbits, a gopher, beaver, voles, shrews, llamas, a grison (a mink-like animal), and a small carnivore (Table 1). The finds include a new genus of minnow and a new species of sunfish. New types of fossils are being found each time we look, so this list is likely to grow!
Since 2006 we have been carefully sieving the sediment layers at the Always Welcome Inn site to determine where different types of fossils are located (Figure 4). This is helping us better understand the environments and the ecological relationships of the plants and animals that were here millions of years ago.
HOW OLD ARE THE ALWAYS WELCOME INN FOSSILS?
We do not know exactly how old the Always Welcome Inn fossils are. The sequence that contains the Always Welcome Inn fossils was mapped in 1976 as early Pliocene (5-3.4 million years old) by Howard Brooks, J.R. McIntyre, and George Walker. We had an ash from the sequence Ar/Ar dated and the age came out around ~15 million years old—the ash was evidently eroded from older deposits upstream and washed into the Always Welcome Inn area. The types of voles and beaver found at the Always Welcome Inn suggest an age in the lower part of this range. Right now our best guess is that the Always Welcome Inn fossils are approximately 5-4 million years old. Further study of the fossils may help narrow this range even more.
Figure 4. The Always Welcome Inn sedimentary sequence, showing the distribution of diatomite (Dia), silt (sSlt), silty sand (sltS), gravel (Gr); and fossils in the sequence. Percentages of sponges and diatoms in the sediments are based on point counts and the abundance of fish, frogs and salamanders was determined by sieving a known volume of sediment from each interval.
Table 1. List of fossils from the Always Welcome Inn locality. ________________________________________________________________________
Kingdom PROTOCTISTA
Phylum BACILLARIOPHYTA (diatoms)
Anomoeneis Fragilaria
Aulacoseira Navicula
Cocconeis Nitzchia
Cyclotella Rhopaloidia
Epithemia
Phylum CHLOROPHYTA
Class CHAROPHYCEAE (Charophytes)
Kingdom PLANTAE
Root casts
Leaf and wood fragments
Kingdom ANIMALIA
Phylum PORIFERA (sponges)
Ephydatia fluviatilis (sponge spicules)
Phylum MOLLUSCA (clams. snails, octopus, and their relations)
Class GASTROPODA
Family Lymnaeidae (snail)
Family Planorbidae
Gyraulus (snail)
Class BIVALVIA (bivalves)
Family Sphaeriidae
Genus Sphaerium Scopoli, 1777 (clam)
Genus Pisidium Pfeiffer, 1821 (clam)
Phylum ARTHROPODA
Subphylum CRUSTACEA
Class OSTRACODA (ostracods)
Phylum CHORDATA
Subphylum VERTEBRATA
Class OSTEICHTHYES
Family Centrarchidae
Genus Archoplites Gill 1862
Archoplites, sp. nov. (sunfish)
Family Cyprinidae
Genus Achrocheilus Agassiz (minnow)
Genus nov. (minnow)
Class AMPHIBIA
Order Anura
Family Ranidae
Rana? (frog)
Order Caudata
Family Ambystomatidae
Ambystoma (salamander)
Class REPTILIA
Order Squamata
Family Colubridae
Thamnophis or Nerodius? (snake)
Subclass Anapsida
Order Testudine
Family Emydinae
Trachemys or Clemmys? (pond turtle)
Class AVES (birds)
Subclass Neognathae
Infraclass Galloanserae
Order Anseriformes (water fowl)
Family Anatidae (ducks)
Infraclass Neoaves
Order Gruiformes (coots, cranes and rails)
Family Rallidae (rails)
Order Strigiformes Wagler 1830 (owls)
Class MAMMALIA
Order LIOPOTYPHLA Haeckel 1866 (INSECTIVORA)
Family Soricidae Fischer von Waldheim 1817
Genus Paracryptotis
Paracryptotis rex (shrew)
Order LAGOMORPHA (rabbits, hares, and pikas)
Family Leporidae
Hypolagus? (extinct hare)
Order RODENTIA Bowditch, 1821
Family Geomyidae Bonaparte 1845 (gopher)
Family Castoridae (beavers)
Genus Castor Linnaeus 1758
Castor californicus Kellogg 1911
Genus Dipoides Jäger, 1835
Dipoides cf. vallicula Shotwell, 1970 (extinct beaver)
Family Cricetidae Rochebrune, 1883 (primarily New World mice and rats)
Subfamily Arvicolinae Gray, 1821 (voles, lemmings, and muskrats)
Genus Ophiomys Hibbard and Zakrzewski, 1967
Ophiomys sp. (extinct vole)
Order ARTIODACTYLA
Family Camelidae (extinct llama?)
Order CARNIVORA
Family Mustilidae
Genus Trigonictis (grison)
Small carnivore
WHAT WAS THE ENVIRONMENT LIKE DURING THIS TIME PERIOD ?
The types of sediments and fossils present in the Always Welcome Inn sequence suggest that this area was located at the margin of a lake. The types of fish, diatoms, gastropods, bivalves, and sponge spicules indicate that the environment was rather warm and the water depth was not extremely deep. The sands and silts in the upper part of the sequence appear to have been deposited by a stream which flowed into the lake. Charophytes, reeds, and other plants grew along the lake margin. Birds, frogs, salamanders, voles, beaver, and other mammals thrived in the area (Fig. 5, 6).
Overall, the sediments and fossils at the Always Welcome Inn fossil site record a change from shallow lake to stream environments. The type of sunfish present in the Always Welcome Inn outcrop suggests that the elevation was probably below 1000 m (3,281 ft), which is slightly lower than the present elevation of the outcrop (~1050 m or ~3,440 ft). Precipitation was probably much higher than what falls in the area today. The area around the lake and the surrounding hills may have been forested with trees similar to those that grew during the late Miocene to early Pliocene on the northeast side of the Powder Valley and on the flanks of the Wallowa Mountains near Keating, Oregon. These included maple, hornbeam, hickory, sweetgum, magnolia, tupelo gum, oak, redwood, swamp cypress, and water chestnut.
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Figure 5. Schematic trophic structure of the Always Welcome Inn local fauna.
Figure 6. Schematic block diagram illustrating the paleogeography and geology of the Always Welcome Inn area during the early Pliocene. The block diagram shows the area during a period of lower lake levels. At higher lake levels the two lakes may have merged into one. Rock unit symbols include: Tcrb (Columbia River Basalts); Tst (Tertiary sediments and tuffs); and Tpr (Powder River volcanics).
WHY ARE THESE SEDIMENTS LOCATED HIGH ABOVE THE VALLEY FLOOR
After the Always Welcome Inn lake and stream sediments were deposited, they were tilted, eroded, and uplifted by mountain-building activity. The sequence is cut by a dozen normal faults that have a total offset of ~7.3 m, including one fault that has an offset of over 1 meter. Faulting has lifted the lake beds well above the valley floor. According to Howard Brooks and his colleagues, this tells us that the lake basins were larger than the present valley. After the faulting, the tilted lake and stream beds were eroded and covered with the gravels visible in the upper part of the outcrop. These gravels were deposited by streams that originated in the nearby mountains and flowed toward the northwest. The influx of gravels probably reflects accelerated uplift of the nearby mountains and, possibly, the entrenching of the Powder River and the formation of the canyon between Thief Valley Reservoir and Keating during the period that Lake Idaho, the great lake that once occupied the western Snake River Plain, drained out through Hells Canyon. This occurred between ~3-2 million years ago.
WHY ARE THE ALWAYS WELCOME INN FOSSILS IMPORTANT?
The Always Welcome Inn fossils are a puzzle piece telling us what the Powder Valley area was like ~5-4 million years ago. The sequence includes salamanders that stayed in the larval form throughout their lives. A new genus of minnow and a new species of sunfish at the Always Welcome Inn tell us that the ancestral Powder River did not drain into Lake Idaho or the Columbia River at the time that the Always Welcome Inn sediments were deposited. We may have one or more types of beaver at the Always Welcome Inn. One of these (Dipoides) is an ancestor of the giant beaver of the Pleistocene. The primitive Always Welcome Inn voles are providing new information on how voles may have migrated up the Columbia River and into the Powder Valley area during a warm and wet period ~4.8 million years ago and from the Always Welcome Inn eastward to the area of Hagerman, Idaho, by ~3.7 million years ago. The study of these fossils may help us better understand the evolution of voles and their migration from the Pacific coast eastward to the Midwestern United States. And we have found a mink-like animal, a grison, which is only found in South America today. The most important thing is that the site provides a place where students can experience first-hand the thrill of finding fossils and piecing together the geology of this area. Each new discovery at the Always Welcome Inn helps us improve our picture of what the Baker City area was like in the geologic past. There is still a lot more to learn!
THE ALWAYS WELCOME INN FOSSILS
(Note: EO-xxx refers to the Eastern Oregon University sample number for the fossils.)
Diatoms
Planktic (floating) and benthic (bottom-dwelling) diatoms are common in the thick diatomite layers in the lower part of the Always Welcome Inn sequence, but are also found in the upper part. The genera include Anomoeneis, Aulacoseira, Cocconeis, Cyclotella, Epithemia, Fragilaria, Nitzchia, and Rhopaloidia. Epithemia is commonly found in littoral zones (near the shore) and is an indicator of alkaline water that is somewhat enriched in nutrients. The diatoms are dominantly shallow water forms, suggesting that the Always Welcome Inn site was located near the lake margin.
Figure 7. Planktic (left) and benthic (right) diatoms from near the base of the Always Welcome Inn sequence.
Plants and Charophytes
Charophytes (also known as stoneworts) are large algae that range in size from a few millimeters to over a meter in length. They are found primarily in freshwater, but also grow in brackish and semi-terrestrial environments. They have gained even more attention recently because they are now known to be the most closely related group of organisms to land plants. Unlike other green algae, the charophytes have a method of cell division called “phragmoplasts”, which is also found in land plants.
Fragments of charophytes are very common in the Always Welcome Inn sequence (Fig. 8). It is possible that some of the fossils we have identified as charophytes may be rushes or reeds. The base of the sequence also contains organic-rich layers (lignites) that contain abundant broken and fragmented leaves that are difficult to identify. Root casts are abundant in the upper part of the sequence. We still have a lot of work to do to identify the plants and we are hoping to study the pollen in the sequence to see what the vegetation surrounding the Always Welcome Inn was like. Perhaps it will match up with the plants found in the Keating area, but we don’t know that yet.
Figure 8. Plant fossils from the Always Welcome Inn sequence (EO-767). These may be charophyte stem fragments.
Sponges
The spicules of freshwater sponges are abundant in the lower part of the Always Welcome Inn outcrop. The most common sponge is called Ephydatia lacustris. This species prefers water depths less than 1.5 m with a pH of 6-8 and temperatures of 12-34°C. It is common in lakes and ponds.
Figure 9. Freshwater sponge spicules (arrows) in a matrix of diatoms and organic matter.
Gastropods
Gastropods are very abundant in the lower part of the Always Welcome Inn sequence (Fig. 10). Terry Frest identified the shallow, warm-water gastropod Gyraulus, along with a group of gastropods called lymnaeids. There may be others as well. More study of the gastropods would be a great help in understanding the environments the Always Welcome Inn sediments were deposited in.
Figure 10. Gastropods from the Always Welcome Inn sequence (EO-803).
Bivalves
The bivalves Sphaerium and Pisidium were first identified in the Always Welcome Inn sequence by Terry Frest. Like the gastropods, these small clams (Fig. 11) are usually found in shallow, warm water. They are very abundant in some of the layers in the Always Welcome Inn sequence.
Figure 11. Bivalves from the Always Welcome Inn sequence (EO-794).
Ostracods
Ostracods belong to the class Crustacea, which also contains lobsters and crabs. They are tiny, usually less than a millimeter across. The paired body parts are enclosed in a hinged carapace. Ostracods are found today in almost all aquatic environments, including the ocean, lakes, hot springs, and caves. The ones in the Always Welcome Inn sediment look a lot like tiny peas (Fig. 12). We are hoping to learn more about them soon!
Figure 12. Ostracods from the Always Welcome Inn sequence (EO-944).
Fish Fossils
The Always Welcome Inn fish fossils include the bones of an undescribed genus of the minnow family, Cyprinidae (Fig. 13). Approximately 170 fragments of minnow bones were collected by Terry Frest and E. Johannes on April 21, 2002. These include spines, jaws, and parts of the skull. Careful examination of the fossils has shown that the Always Welcome Inn genus is different from all other western North American cyprinid genera, although it shares some traits with members of the clade containing Pogonichthys, Mylocheilus, and Richardsonius. The closest resemblances are with fish found in the Sacramento River drainage basin.
David Whitson was the first to find a tooth of Achrocheilus, another minnow in the Family Cyprinidae, at the Always Welcome Inn (Figure 13). It resembles the teeth of the Snake River chiselmouth chub, Achrocheilus latus (Cope). Achrocheilus has also been found in the Taunton local fauna of Washington.
Bones of a new species of the genus Archoplites of the sunfish family Centrarchidae are widespread at the Always Welcome Inn locality (Fig. 14). The Always Welcome Inn species has characteristics that show that it is different from all other known Archoplites. It is apparently not closely related to the sunfishes from the Chalk Hills, Glenns Ferry, or Ringold Formations. Two growth forms of sunfish occur in the Always Welcome Inn fauna. Bones of a form characteristic of lake and pond sediments are common in the lower part of the section. These bones are delicate and fragile, from fish about 130 mm in standard length (body length excluding the caudal fin) that live 7 or 8 years without growing much larger. A form characteristic of stream sediments is also found, especially in the upper part of the sequence. This form has robust bones, about twice the growth rate of the lake and pond form, and reaches larger sizes.
The limited sizes and lack of fish diversity at the Always Welcome Inn site contrast with the Snake and Columbia River fish faunas in the Pliocene. The sharp morphological differences between the minnow and sunfish of the Always Welcome Inn site from the Miocene and Pliocene forms from localities in California, Oregon, Washington, Idaho, and Nevada indicate long-term isolation. Furthermore, the absence of diverse suckers, minnows, salmonids, catfish, and sculpins argues against any long-term aquatic connection with the Pliocene Snake and Columbia Rivers, which had diverse fish faunas.
Figure 13. Minnow teeth from the Always Welcome Inn: Left: a new genus of minnow (EO-900); Right: Achrocheilus (EO-766).
Figure 14. Sunfish (Archoplites) fossils from the Always Welcome Inn (F). A. Sunfish spine (EO-762.1), B. Sunfish vertebra (EO-819), C. Sunfish scale (EO-779.24), D. Sunfish lacrymal (EO-762.2), E. Sunfish maxilla (EO-762.3) and F. Sunfish preopercle (EO-776.11). Scale bars are in millimeters.
Frogs and Salamanders
The Always Welcome Inn herpetofauna consists of small anurans (frogs and toads, yet to be described) and a single taxon of salamander (Fig. 15). Our best guess at present is that the frogs belong to the family Ranidae, one of the most common frogs in many Pliocene deposits, including the Glenns Ferry Formation of Idaho. The size of the salamander vertebrae and the position where the spinal nerve exits the spinal column between the vertebrae suggest that the Always Welcome Inn belongs to the family Ambystomatidae.
One very interesting feature of the Always Welcome Inn salamander vertebrae is that most of the centra of the very large vertebrae show a continuous passageway for the notochord; the septum has not developed. This persistence of the notochord illustrates that most, if not all, of the salamander vertebrae are from relatively young (albeit large) larval (neotenic) forms. This suggests that the salamanders stayed in the water throughout their lives rather than moving up onto land.
Figure 15. Salamander dentary fragments (A and B) and vertebrae (C and D) from the Always Welcome Inn (EO-866). Scales are in millimeters.
Snakes
We didn’t know that we had snake fossils at the Always Welcome Inn until May 2007, when Dr. James Mead identified a vertebra found by Misty Davis, an Eastern Oregon University student, as a snake. Later, Dr. Mead identified another snake vertebra in the Eastern Oregon University collection that had been mistakenly mixed in with salamander fossils (Fig. 16).
Snakes are mostly vertebrae and ribs, so it is not surprising that vertebrae are the parts of snakes that are most commonly found. Each snake vertebra connects to the one before and behind it via a ball and socket system, which provides the flexibility in the backbone that allows the snake to slither along. Fortunately, the shape of the processes where muscles attach and the proportions of the vertebrae differ enough in different snake species that it is often possible to tell different snake species apart from only a single vertebra.
Dr. Mead is currently examining the Always Welcome Inn snake vertebrae to determine which species it is. Our best guess at present is that it is either a garter snake (Thamnophis) or a water snake Nerodius).
Figure 16. Snake vertebra (EO- 945).
Turtles
Fossil turtle shell was first found at the Always Welcome Inn outcrop in June 2006 by RuAnn Barnard, an Eastern Oregon University geology student (Fig. 17). The discovery was made near the base of the sequence. We do not yet know which genus the turtle belongs to. Perhaps it is Trachemys, the slider turtle, or Clemmys, the pond turtle, which are both found in the fossil beds at Idaho. The living species of both Trachemys and Clemmys are aquatic turtles that stay mainly in the water. Along with the beaver, frogs, salamanders, and waterfowl, the turtles support the interpretation that the Always Welcome Inn was an extensive wetlands area during the time the sequence was deposited.
Figure 17. Fragments of turtle shell found in the lower part of the Always Welcome Inn sequence (EO-728).
Birds
Bird fossils are turning out to be more common at the Always Welcome Inn than we first thought (Fig. 18). The first bird fossils at the Always Welcome Inn were found by Angela Sanderson of the University of Montana and Cassie Bloom, a student at Pine-Eagle High School. Dr. Dave Steadman of the Florida State Museum was not able to positively identify these bones, but, according to Dr. Steadman, “they probably quacked.” Corby Weyhmiller, a student at Eastern Oregon University found two bird bones in April 2007 that Dr. Steadman identified as the carpometacarpus of a rail and a tarsometarsus of a duck. Dr. Greg McDonald discovered a coracoid of a bird in June 2007 that has yet to be identified. We have also discovered the claw of a raptor, probably an owl. The size of the claw is the size of the claws of modern short-eared owls (Asio flammeus). Pliocene Asio fossils have also been found in the ~4.3 Ma Fox Canyon locality in Kansas and the ~3.7-3.1 Ma Hagerman fossil beds. We have also discovered numerous fragments of egg shells in the Always Welcome Inn sediments, but we do not yet know what types of birds these shells came from. The bones of many of the small rodents at the Always Welcome Inn may have come from owl pellets and castaways.
Figure 18. Bird bones from the Always Welcome Inn sequence. From top to bottom: Coracoid (EO-933); rail carpometacarpal (EO-918); duck? (EO-768); duck tarsometatarsal (EO-917); and duck? (EO-897).
Shrews
Shrew fossils are very difficult to find because of their small size. A shrew jaw is typically only 11 mm or one-half inch long. We were very lucky to spot a shrew tooth while sorting through sediments that had been wet-sieved through a 0.5 mm sieve (Fig. 19). We were looking for teeth of cricetid rodents, but found the shrew tooth instead. Fortunately, since bones and skulls of small animals are easily broken and unlikely to be preserved, the teeth are the most distinctive parts of the animal and are often used to identify them. Our latest find is the lower left jaw of a juvenile shrew, which was found by Dr. Greg McDonald of the National Park Service in June 2007. Based on the size and other characteristics of the adult lower second molar, we have identified the Always Welcome Inn shrew as Paracryptotis rex.
Paracryptotis rex was first collected and described from the ~4.3 m.y.-old Fox Canyon and Wendell Fox localities of the Rexroad Formation of Kansas. It has also been found in the ~9-7 m.y.-old Rome fauna of northeast Oregon, the ~4.8 m.y.-old Saw Rock Canyon fauna of Kansas, and the ~3.9 m.y.-old Blufftop fauna of Washington. Like many of the other small mammals found at the Always Welcome Inn, this shrew probably preferred wet marshy environments.
Figure 19. The lower left second molar of an adult shrew (top; EO-935) and the lower left jaw of a juvenile shrew jaw with incisor, P4 (broken), and intact first and second molars (bottom; EO-971) found at the Always Welcome Inn).
Hares
We’ve found only two hare fossils at the Always Welcome Inn site. The first is a metatarsal or metacarpal bone found on the surface of the outcrop (Fig. 20). The second is a tooth found in a bulk sample from the outcrop by Dr. Jim Mead (Fig. 21). The tooth appears to be similar to the upper first molar of the leporid Hypolagus gidleyi, one of the fossil hares found in the Hagerman beds of Idaho, but it also resembles Hypolagus vetus fossils found in the Rattlesnake Formation of Oregon. It seems likely that the Always Welcome Inn hare belongs to the genus Hypolagus, but fossil hare classifications are not based on upper first molars, so we’ll have to find a diagnostic tooth before we know for sure what species the Always Welcome Inn hare belongs to.
Figure 20. Metatarsal/metacarpal of a hare (EO-872).
Figure 21. An upper molar from a hare (EO-932). The overall shape and the crenulations in the reentrant on the occlusal (biting) surface of the tooth suggest that the Always Welcome Inn hare is Hypolagus.
Gophers
An lower first or second molar of a juvenile pocket gopher was found in the stream sediments in the upper part of the Always Welcome Inn sequence on October 11, 2007 by Ken Brasel and Jay Van Tassell (Fig. 23). Pocket gophers are burrowing rodents of the family Geomyidae. These are “true” gophers, unlike some ground squirrels which are often called gophers as well. Most pocket gophers weigh a few hundred grams. They are named for their large cheek pouches, which are fur-lined and can be turned inside out.
We do not know yet which genus of pocket gopher the tooth came from. It is possible that it is related to Thomomys gidleyi wilson, a species of pocket gopher that was first described in the Hagerman Fossil Beds of Idaho. Thomomys sp. has also been described in the Wildhorse locality in Eastern Oregon and a species very similar to Thomomys gidleyi was noted in the White Bluffs Formation of Washington. Another possibility is that the Always Welcome Inn pocket gopher is related to Pliogeomys parvus, a species which has been found in the Hagerman Fossil Beds.
Figure 23. An lower first or second molar from a pocket gopher (EO-977).
Beaver
The first beaver fossil found at the Always Welcome Inn was a left upper first molar tooth found in October 2005 by Elizabeth Burton, the director of Eastern Oregon University’s Distance Education program in Baker City (Fig. 24). The tooth has the almost square occlusal outline that is typical of Dipoides. It is difficult to assign an isolated tooth to a species of Dipoides because male/female dimorphism, regional variations, age, etc. all play a role. Because the pattern of the biting (occlusal surface) resembles one from molars of Dipoides vallicula from Little Valley, Oregon (near Vale), we have decided to refer to the species as Dipoides sp. cf. vallicula until additional material to confirm the identification is found. The Always Welcome Inn tooth also resembles Dipoides wilsoni, a species found in ~4.8 million year-old Sawrock Canyon fauna of Kansas.
Modern beaver belong to the genus Castor, which apparently migrated to North America over six million years ago and has undergone little evolutionary change ever since. Dipoides, on the other hand, evolved into the giant Pleistocene beavers Procastoroides and Castoroides, which reached the size of a small bear. There were two lineages that led to giant beavers. One stemmed from Dipoides stirtoni, a species found in the late Miocene beds near Rome, Oregon. The other lineage started with the smaller species, Dipoides wilsoni. It is likely that the species found at the Always Welcome Inn is an important link in this second line of descent, which led to the much larger beaver, Dipoides rexroadensis, found in the ~4.3 million year-old White Bluffs fauna in the Columbia River drainage basin, and then to the giant Pleistocene beaver Castoroides ohioensis, which was the same size as “Castoroides” kanasensis, which resulted from the Dipoides stirtoni lineage.
In April 2007, Adora Brockman, a seventh-grade student at Pine-Eagle High School, found a left lower jaw at the base of the Always Welcome Inn sequence that Dr. Greg McDonald identified as a the fossil beaver Castor (Fig. 25). Matt Smith, the preparator at the John Day Fossil Beds National Monument, did an outstanding job separating the jaw from the matrix and exposing the biting (occlusal) surfaces of the teeth. The beaver that Adora Brockman found is Castor californicus.
Figure 24. Dipoides tooth found at the Always Welcome Inn (EO-765). Scale bar is in millimeters.
Figure 25. The lower left jaw of a beaver (Castor californicus) found at the base of the Always Welcome Inn sequence (EO-919). This sample was prepared by Matt Smith (John Day Fossil Beds National Monument).
How could two species of beaver have lived together in the same area? To find out, Natalia Rybyczynski of the Canadian Museum of Nature in Ottawa modeled the incisors of both genera in steel and experimented with different wood types to see how well each incisor worked. She discovered that Dipoides teeth were specialized for chewing trees similar to red cedar, while Castor incisors were better suited for exploiting a number of woody vegetation types compared to those of Dipoides. This demonstrates that the two types of beaver ate different types of vegetation.
Arvicolid Rodent (Vole) Fossils
Voles are one of the most rapidly evolving animals preserved in the fossil record. This makes them very useful for determining the age of fossil sequences. Our first vole fossils, a molar and two incisors from a juvenile vole, from the Always Welcome Inn outcrop were found by April Leithner in April 2005. To date, the Always Welcome Inn sediments have produced one jaw (found by Dr. Greg McDonald in June 2007) and 15 molars from a primitive vole, plus four incisors that may be from the same species (Figs. 26, 27).
The identity of the Always Welcome Inn vole remains a puzzle. Many of the characteristics of the Always Welcome Inn vole teeth resemble those of 4.8 million year-old vole teeth found near Panaca, Nevada, suggesting that that the Always Welcome Inn vole may be close to the same age. Careful study of the patterns of the occlusal (biting) surfaces of the Always Welcome teeth by Dr. Robert Martin suggests that the Always Welcome Inn vole belongs to the genus Ophiomys and may be an ancestor of Cosomys, a fossil vole found at Hagerman, Idaho. This suggests an age range for the Always Welcome Inn vole of ~4.8-3.7 Ma, older than the 3.7-3.1 Ma age of Cosomys at the Hagerman site and younger than the time when arvicolid rodents of the genus present at the Always Welcome Inn site first arrived in North America from Siberia.
One of the modern voles in the family that Ophiomys belongs to is Arvicola, a water vole. It is possible that Ophiomys was also a water vole, but it is difficult to tell from the fossil record whether or not this is true.
If we can nail down where the Always Welcome Inn vole fits into the vole evolutionary sequence, it may be an important piece in understanding the waves of migration of microtine rodents into the western United States during the late Miocene and Pliocene. We know that the primitive vole Promimomys (Prosomys) migrated from Eurasia south along the Pacific coast of North America and up the Columbia River drainage to the McKay Reservoir site near Pendleton, Oregon, ~6.7 million years ago and can understand why Promimomys did not migrate up the Sacramento River and into the Lake Idaho area during this period because the level of the Chalk Hills phase of Lake Idaho was dropping to its lowest level due to tectonic movement and down cutting of its outlet at this time. But, it is a puzzle why both the voles Ophiomys and Cosomys migrated from Siberia south along the Pacific Coast during the next wave of vole migration at ~4.8 Ma and worked their way up the Sacramento River system to Hagerman, Idaho, by ~3.7 Ma, while only Ophiomys migrated up the Columbia River system, reaching the area of White Bluffs, Washington, at ~4.3 Ma. The presence of a possible ancestor of Cosomys in the Always Welcome Inn fauna suggests a number of possible explanations to this problem. Perhaps Ophiomys migrated directly up the Sacramento River system to Lake Idaho and entered the Columbia River drainage basin from the east through the Always Welcome Inn area? Or, is it possible that the Cosomys in the Hagerman area was derived from the Ophiomys in the Always Welcome Inn area and migrated to Hagerman during a later migration event between ~3.7-2.9 Ma at the same time that fish and muskrats migrated westward from the Lake Idaho in the Snake River Plain area to the Columbia River drainage basin? Very rare Lake Idaho diatoms, fish fossils, and volcanic ash layers found in a well in the Grande Ronde Valley near Imbler, Oregon, suggest that Lake Idaho drained through the Powder and Grande Ronde Valleys to the Columbia River drainage at ~3.8-3.7 Ma and ~3.2-3.0 Ma. This may have facilitated the migrations from east to west and vice versa
We need to find more fossils to fill in the missing pieces in both of the possible scenarios of vole migrations outlined above, but one thing is clear: All of the major microtine migrations from 6.7-3.2 million years appear to have occurred during times of wet climate. More work is needed to understand this link.
Figure 26. Vole lower jaw with first molar found by Greg McDonald (EO-935).
Figure 27. Vole teeth from the Always Welcome Inn. L: left; R: right; m: lower; M: upper. 1,2,3: First, second, third molars. The occlusal patterns of the teeth are shown in the lower half of the diagram. All the molars have two roots except the right second and third upper molars, which have three roots. Sample numbers: Incisor (EO-771A), LM1 (EO-878B), RM2 (EO-832A), LM3 (EO-879), RM3 (EO-838A), Lm1 (EO-878A), Rm1 (EO-881), and Lm2 (EO-832B).
Grison
The mustelid family includes skunks, weasels, badgers, and wolverines, a group of animals that all have well-developed scent glands. Our first mustelid bone at the Always Welcome Inn site was collected by Corby Weyhmiller in April 2007 (Fig. 28). Corby noticed the end of the bone sticking out and carefully scraped away the surrounding sediment, revealing a delicately curved humerus. The bone was broken into two parts, so we did our best to glue it back together again. Dr. Greg McDonald has identified the fossil as a juvenile Trigonictis, a member of the mustelid family known as a grison. Grison fossils were described in the area of Hagerman, Idaho, by C.L. Gazin in 1934. The modern grison (Galictis), a carnivore that lives in South America, was derived from North American ancestors. It is about the size of a pine marten and its body is elongated like those of minks and weasels. This is the largest predator we’ve found so far at the Always Welcome Inn.
Figure 28. Photograph of the humerus of the grison, Trigonictis.
Small Carnivore
One of the most puzzling finds at the Always Welcome Inn is the tooth of a small carnivore found near the top of the sequence (Fig. 29). We don’t know what animal it came from and we don’t even know for sure if it is a fossil. It is possible it came from a modern animal that died in this area only recently.
Figure 29. Tooth of a small carnivore found at the top of the Always Welcome Inn sequence.
Camelid: Llama?
One of the guests at the Always Welcome Inn spent several hours looking for fossils and found the bone of the largest animal discovered so far (Fig. 30). The bone is from a camelid, possibly a llama. We do not know where in the sequence it was collected, but we are guessing it came from the gravels that cap the sequence. If true, this would mean that it is younger than the other fossils from lower in the section. It may be ~3-2 million years old. We’re hoping to discover more so we can pinpoint where it came from. We have found some bone fragments lower in the sequence that Dr. William Akersten of the Idaho Museum of Natural History suggested may be from a camelid.
One of the interesting parts of the Always Welcome Inn fauna is the relative scarcity of large mammal fossils compared to the abundance of small animals such as fish, salamanders, and voles. This may reflect the environment at the time of deposition, which may have been better for the preservation of small fossils as opposed to large bones. Paleontologists refer to this as the taphonomy or “preservation potential” of the site. Or, perhaps there are more bones of large mammals buried beneath the surface of the outcrop, waiting to be discovered.
Figure 30. Camelid bone, possibly a llama distal metapodial (EO-785), found in gravels above the unconformity at the top of the section. The left hand picture is a medial view and the right hand picture is a ventral view. Scale is in mm.
Acknowledgments
We are very grateful to the Langrells, the owners of the Always Welcome Inn, and their staff for allowing us to study this site and for their interest and help throughout the course of this project. We greatly appreciate the help of all the paleontologists who have worked with us on this project. The enthusiasm and help of Laura Mahrt, John Rinehart, and Joe Corsini of the Eastern Oregon University biology department are greatly appreciated. This project wouldn’t have been possible without the encouragement and assistance of Mark Ferns, Jan Durflinger, and Jason McClaughry of the Oregon Department of Geology and Mineral Industries. Jeff McDonald of Eastern Oregon University’s Pierce Library has searched out numerous paleontology papers that have helped us better understand what the fossils at the Always Welcome Inn are telling us.
Special thanks go to all of the people who have helped us collect fossils at the site and donated their finds to our collection, including: RuAnn Barnard, Cassie Bloom, Lisa Bluhm, Adora Brockman, Elizabeth Burton, Calvin Davis, Lynna Fischer, Bill Gaertner, Brooke Garton, Michael Jaeger, Kelby Killgore, Allison Kuenzli, Bob Larison, Henrietta Laustsen, April Leithner, Jason and Annie McClaughry, Greg McDonald, Vicki McConnell, Jim and Sandy Mead, Angela Sanderson, Klista Starner, Takeshi Sugimoto, Kelsey Swanson, Troy Tubbs and his students at Pine-Eagle high school, David Whitson, Corby Wehymiller, Mike Woydziak, and Nick Zolotoff. This study would not have been possible without their enthusiasm and help.
USEFUL REFERENCES
Brooks, H.C., McIntyre, J.R., and Walker, G.W., 1976, Geology of the Oregon part of the Baker 1° by 2° quadrangle: Oregon Department of Geology and Mineral Industries GMS-7,1:250,000.
Burton, E., and Van Tassell, J., 2005, Fossil beaver (Dipoides) tooth, Always Welcome Inn, Baker City, Oregon: Eastern Oregon Geology, v. 3, 10 p. (http://www.eou.edu/~geology).
Davis, C.; Bluhm, L.; Killgore, K.; Kisselburg, J.; Ledgerwood, R.; Starner, K.; Steele, J.; Zolotoff, N.; Van Tassell, J.; Ferns, M.L.; and Smith, G.R., 2005, Fossils, stratigraphy, and structure of the Always Welcome Inn outcrop, Baker City, Oregon [abs.]: Geological Society of America Abstracts with Programs, v. 37, no. 6, p. 8.
Hoxie, L.R., 1965, The Sparta flora from Baker County, Oregon: Northwest Science, v. 39, no. 1, p. 26-35.
Kisselburg, J., 2006, Semi-quantitative analysis of the distribution of fossils in the upper third of the Always Welcome Inn sequence, Baker City, Oregon: Eastern Oregon Geology, v. 3, 9 p. (http://www.eou.edu/~geology).
Van Tassell, J., Ferns, M., McConnell, V., and Smith, G.R., 2001, The mid-Pliocene Imbler fish fossils, Grande Ronde Valley, Union County, Oregon, and the connection between Lake Idaho and the Columbia River: Oregon Geology, v. 63, p. 77-84, 89-96.
Van Tassell, J., Bergey, E., Davis, M., Grimshaw, B., Miller, S., Morris, C., Ferns, M.L., Smith, G.R., McDonald, H.G., and Mead, J.I., 2007, New discoveries at the Pliocene (early Blancan) Always Welcome Inn fossil site, Baker City, Oregon [abs.]: Geological Society of America Abstracts with Programs, v. 39, no. 5, p. 28.
Van Tassell, J., Steele, J., Ledgerwood, R., Kisselburg, J., Morris, C., Miller, S., Grimshaw, B., Davis, M., Bergey, E., Ferns, M.L., Smith, G.R., McDonald, H.G., Mead, J.I., and Martin, R.A., The Early Pliocene (Blancan) Always Welcome Inn Local Fauna, Baker City, Oregon: Oregon Geology, in press.