August 10, 1981

Robert B. Blodgett
Department of Geology
Oregon State University
Corvallis, OR 97331

Dear Bob:

I have completed my examination of the Alaskan trilobite material from the McGrath Quadrangle of Alaska. Certainly the most interesting result is the presence of the genus Camsiella represented by a new species in at least two of the collections. Heretofore this genus has been known only from the Hume Formation, District of MacKenzie, Northwest Territories. Its presence in these Alaskan collections would tend to strengthen the Hume affinities of other faunal groups from the McGrath Quadrangle collections would support an Eifelian age. I have enclosed a xerox of a photo of this new species of Camsellia which you might be interested to compare with Plate 1, Figures 12 and 13 my 1976 paper. The new species differs from truncata in having a few more axial rings and a slight post-axial notch (larval notch) in the posterior border. Another trilobite worthy of note is the Scutelliud in sample A-1217. The development of the glabellar furrows is consistent with a Frasnian age, but this apparently represents a new genus distinguished by glabellar proportions. There is nothing comparable to this taxon in the literature. This new Scutelliud has a distinctive glabellar shape as reflected by the ratio of anterior to basal glabellar width which is 1.38 for the new genus as compared with rations of two other Frasnian species, costatum at 2.22 or thomasi at 2.20.

The identifiability of the McGrath Quadrangle material is, of course, limited by the relatively poor state of preservation. Thus the comparison to setosa is simply the best I can do with the material available. Were more and better preserved material available, I might be able to diagnose this as a new and distinctive taxon. Here are the identifications I have been able to make: (see faunal list):

I hope that this information will be some use to you and would be happy to look at any more material you may have available from the Lower and Middle Devonian of Alaska.

Best regards,

Allen R. Ormiston