|
Reference
|
| Title: |
Report on Referred Fossils
,
1953
(10/23)
|
|
|
| Report by: |
James Steele Williams
|
| Referred by: |
Joseph M. Hoare
|
|
|
|
| | Age: | Permian (late Paleozoic, probably Permian) |
|
|
|
|
|
|
| Comment: | This shipment consists of one collection 52AHr324a which is Paleozoic in age, probably Permian. The collection contains fragmentary brachiopods, a gastropod, and small pieces of other fossils. Mr. Yochelson has made a separate report on the gastropod. In addition to the above invertebrates there are numerous pieces of group prismatic crystals of aragonite such as often found along the hingelines of Inocerami but which also occur on other pelecypods, some of which occur in late Paleozoic rocks. The brachiopods include several productoid forms whose generic affinities cannot be accurately determined with the material available, and isolated groups of striae that may belong to a spiriferoid type of brachiopod and portions of the surface of a brachiopod which resembles in so ar as these surface portions are preserved a. cleiothyridinoid genus. This collection is clearly of late Paleozoic age but it is not possible to say definitely whether it is Mississippian, Pennsylvanian or Permian. From small clues which might be misleading, I believe that it is probably Permian in age, but this conclusion cannot be positively stated because the material is not sufficiently diagnostic to permit a positive conclusion.
Discussion
I examined this material first shortly before I went to the hospital in about March, 1953. I was quite impressed with the several remains of prismatic hinge structure that resembled portions of the hinges of Inoceramus so many of which Reeside and I had seen preserved in this manner in Cretaceous rocks in the west, I also recognized Paleozoic brachiopods in the collection. I showed the material to J.B. Reeside, who, as you know, is a specialist in Mesozoic rocks, and he later showed it to Arthur Cooper. Finally the conclusion was reach that the prismatic structures were parts of the hinges of specimens of one of the Late Paleozoic pelecypods that we all knew about but not recently seen in such numbers and that the Late Paleozoic brachiopods were not reworked forms. Further preparing disclosed more remains of Paleozoic brachiopods and now it is rather certain that the age of the collection is Paleozoic.
I made an oral report to one of the Alaskan men who happened to be in Washington last spring but suppose this report did not reach you.
On reciept of your recent letter, this material was shown by my preparator, Harold Saunders, at my request, to Ralph Imlay. He agreed that it was not Mesozoic. As soon as I saw it, I remembered my previous examination of it and have prepared this report which I was not able to write out after I studied it last spring. |
| Occurrence(s) |
| No. |
Group |
|
Name |
Qty |
Notes |
| 1 |
Brachiopods |
|
several productoid forms whose generic affinities cannot be accurately determined with the material available |
|
|
| 2 |
Brachiopods |
|
isolated groups of striae that may belong to a spiriferoid type of brachiopod |
|
|
| 3 |
Brachiopods |
|
a cleiothyridinoid genus |
|
|
| 4 |
Snails |
|
a gastropod |
|
separate report made on this specimen by Mr. Yochelson |
| 5 |
Bivalves |
|
pelecypods represented by numerous pieces of grouped prismatic crystals of aragonite |
|
|
| 6 |
Bivalves |
|
[the above probably represent the genus Atomodesma - comment by R.B. Blodgett] |
|
|
|
|
| Title: |
Report on Referred Fossils
,
1953
(10/23)
|
|
|
| Report by: |
Ellis L. Yochelson
|
| Referred by: |
Joseph M. Hoare
|
|
|
|
| | Age: | Paleozoic-Late Paleozoic (Middle Paleozoic - Late Paleozoic) |
|
|
|
|
|
|
| Comment: | A single gastropod is present in the collection submitted. It is a rather large moderately high-spired pleurotomarian with a protruding selenizone. The shape, although badly crushed, and the inclination of the growth lines suggest Tropidostropha or one of its allies. On the basis of this slight evidence a middle or upper Paleozoic age is indicated.
Pleurotomarian gastropods are much rare in the Mesozoic than in the Paleozoic. They are particularly uncommon in the Cretaceous. I do not know of a Cretaceous pleurotomarian having the shape or kind of selenizone that seems to characterize this specimen. |
|