Dear Bob:

At long last here is your report on the McGrath A-5 Quad. clams from Alaska. Thank you very much for your patience, I apologize for not getting this to you sooner. I am now officially out of administration except for some left over odds-and-ends and it feels good to be back in science.

There is nothing among the McGrath pelecypods and rostroconchs which dasagrees with your Eifelian age and for the most part part they are garden variety genera which can be identified from the literature on the Appalachian Devonian. It is very difficult to evaluate Devonian pelecypod species, because almost monographic work has been done since the late nineteenth century. Most of the McGrath material is highly fragmentary and this also hurts species identification.

Indentification are as follows: (see faunal list)

Devonian rostroconchs are not well known either taxonomically or paleogeographically; the Mulceodens type were probably infaunal with the rostrum and third aperture probably projecting above the sediment-water interface.

There are very few articulated or "butterflied" specimens of pelecypods in these collections; most specimens are single valves indicating some transport. However, on some specimens the ornament is well preserved indicating that they were not transported far. As indicated above, the genera in these collections are widespread in North America, but it is not possible to make species level comparison.s

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

Siegfried Rietschel
Geology Department
Field Museum of Natural History

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

Dear Mr. Blodgett,

thank you very much for yours letters of March 12 and 19, which I found here, coming back from a two weeks excursion; although the material you've sent arrived safely and I looked at it yesterday, but I found no Scribroporella in it.

So I send back to you the six boxes with undetermined fossils as well as one box specimen of Coelotrochium (79RB4). The fossils, which look a little like Scribroporella are mostly amphiporoids.

I take now with me to Germany the six boxes with Coelotrochium (79RB6, 79RB8, 79RB9, 79RB11, 79RB12 and 79WG184). They should be safe from damage, for I take them in my hand baggage during the flight.

My work at Field Museum seems to be very fruitful and I am not so delighted to leave this week, for there is still a lot of half done work, which I have to finish in near future. But that is in the normal experience of a Museum visit.

So I wish you all the best for your work and your exams.

yours sincerely

Siegfried Rietschel

home address: Landessammlungen fuer Naturkunde,
Postfach 4045,
7500 Karlsruhe 1
WEST GERMANY

Ages are in accordance with your statement of probable ages. 79RB16 is Frasnian by all of our usual criteria and the others are most likely Middle Devonian although late Early Devonian cannot be ruled out in all cases.

If 79RB4, 8, 9, and 12 are all the same age, Eifelian (approximately Hume equivalent) seems most likely.

If you have age data from other sources, especially conodonts will appreciate having this information.

If 79RB4, 8, 9, and 12 are all the same age, Eifelian (approximately Hume equivalent) seems most likely.

July 28, 1980

To: Mr. Robert B. Blodgett
Department of Geology, O.S.U.
Corvallis, Oregon 97331

Dear Robert:

List below are the identifications of the tabulates from the Alaskan material you sent me: (see faunal lists)

I have compared your material with the illustrations in Churkin and others (1975)(USGS Prof. Paper 823 A,B,C,D,) and the following comparisons appear reasonable:

Favosites sp. A = Favosites sp. (Pl. 20, fig. 1,2)
Pachyfavosites sp. A = Pachyfavosites sp. (Pl. 20, fig. 3,4)
Pachyfavosites sp. B = Pachyfavosites sp. (Pl. 20, fig. 5,6)
Parastriatopora sp. = Parastriatopora sp. (Pl. 20, fig. 9, 10)

Except for the absence of Heliolites your faunas appear similar in generic composition to the fauna listed in Churkin and others (1975) for the McGrath quad. (p. 33, table 14). The one exceptio to this is your 79RB19 which also contains Parastriatopora sp. which Churkin and others (1975) list from the Sleetmute quad (p. 33, table 15).

The tabulates do not indicate a specific age interval, but they are compatible with the Eifelian age suggested by your conodont, brachiopod, and goniatite evidence.

Hope this information is of help to you. Let me know if I can be of any further help.

Sincerely,

Richard A. Flory
Associate Professor of Geology