To many, the Nahanni is a river of legend and myth, gold and greed, death and murder, and headless corpses. Our Nahanni is a little more benign, but still concerned with the dead -- sublimely beautiful glassy corpses of trilobites

The South Nahanni River arises near the Yukon border, flows past hot springs, cascades over Virginia Falls through the deepest canyons in Canada cut into fossil-bearing rocks that are painted in vivid pastels of bright red and orange. This is the river that justified the establishment of the Nahanni National Park in the Mackenzie Mountains and the designation of a World Heritage Site by UNESCO. It is also a river of myth fuelled by fevered stories about the corpses of Willie and Frank McLeod found in the valley in 1908, robbed of their gold, lashed to trees and missing their heads. The legend is seemingly corroborated by a set of sinister place names for features along the Nahanni -- Headless Range, Deadmen's Valley, Funeral Range, Broken Skull River, and Hell's Gate.

Sunblood Mountain towers above Virginia Falls as a succession of pink, red and orange limestones of Middle Ordovician age (460 Ma). We have studied these rocks and their trilobites at this and many other localities in the Mackenzie Mountains. The collection of trilobites is generally a time-consuming process which involves many hours and even days breaking rock at a single locality to obtain sufficient specimens. The strata on Sunblood Mountain include trilobites, but the Nahanni fossils are preserved like few others -- the calcite of these exoskeletons has been replaced by fine-grained silica. This quirk of preservation is a paleontological windfall because, by slowly dissolving lumps of limestone with weak acids in the lab, we were able to recover thousands of specimens of exquisite trilobites, many of them minute, and each preserved in full relief.

None of the trilobites is preserved intact as a complete animal -- each consists of cranidia, free cheeks, hypostomes, rostral plates, thoracic segments and pygidia of different sizes jumbled together with different elements of more than twenty other species of trilobites. After sorting these silicified specimens (under a microscope), we were able to prepare a comprehensive description of all elements of each species. Moreover, we were able to analyze the growth history of each species from larvae to adult. And we were able to allocate individual trilobites to each of four major ecological communities. We found that the brittle silicified trilobite elements could safely be handled for picking and sorting with insect tweezers. For photography, however, each element had to be affixed with water-soluble glue to the tip of a toothpick which could then be used to orient the specimen underneath the vertically-oriented camera. The larval trilobites, some measuring less than half a millimetre, had to be photographed with a scanning electron microscope.