|NPS Paleontology Research Abstract Volume|
Lower Devonian vertebrate faunas in the western USA are currently known from a small number of localities in Wyoming (Beartooth Butte Formation) and Utah (Water Canyon Formation), and most recently from the Sevy Dolomite of Nevada and Utah. These faunas are most commonly found in sediments filling channels cut into the underlying Lower Paleozoic strata, and appear to record a major transgressive event in which the early Devonian sea advanced to the east.
The new Lower Devonian fauna in Death Valley extends the record of this event to the south and west. It occurs in a large channel at least 150 m deep and 600-800 m wide, located near Trail Canyon on the eastern flank of the Panamint Range. The fauna contains gnathostomes (jawed vertebrates) represented by one placoderm and several acanthodians; and agnathans (jawless vertebrates) represented by one cephalaspid, six cyathaspidids, and six pteraspidids. The agnathan fauna adds considerably to our knowledge of the diversity of these organisms during the Lower Devonian as only one cyathaspidid and ten pteraspidids had been described previously from Utah and Wyoming.
Sufficient genera are found in common between the Death Valley fauna and those previously described to allow them to be correlated. In addition there is sufficient invertebrate dating of the Lippincott member of the Lost Burro Formation to show that the fauna must be late Emsian in age.
Work is continuing to collect a more complete fauna, and to complete studies on the sediments in the channel-fill and their environment of deposition.
|United States Department of the Interior, National Park Service|