For other determinations of Black Cap fossils see my letter of February 13, 1967 to George M. Haselton, a copy of which is attached.

No age determination of this material is possible; I doubt that it can be older than Silurian and it is doubtless Paleozoic.

Several types of bryozoans are present. The small rhomboporoid types did not hold up as well as the larger ramose forms so I was unable to find diagnostic structures. A number of the larger branches exhibit zooecial tubes that are rhombic in transverse section. This feature is characteristic of Rhombotrypella, a genus that ranges from the middle Pennsylvanian into the Permian in conterminous western United States. It is common in the Permian of Alaska. I have no data on bryozoans that may occur in the Pennsylvanian of southeastern Alaska. In view of existing information, I strongly suspect that this collection is of Permian age. An element of doubt exists, however, because there is a Late Ordovician bryozoan - Rhombotrypa - that also has rhombic tubes in the axial region. This genus has been reported in a diversified fauna of Richmond age that was collected in the White Mountains. It would be virtually impossible to differentiate Rhombotrypella from Rhombotrypa without information on the wall structure, which in this case cannot be determined.

Essentially nothing is known about Alaskan Ordovician bryozoans. On the other hand, we do know that Bryozoa are locally abundant in the Permian. All the Alaskan collections in which bryozoans are the predominate fossils that I have examined during the course of years are believed to be Permian. Bryozoans are generally scarces in facies that are favorable for corals. As corals are apparently abundant in much of the Alaskan Silurian, Devonian, and Mississippian, ecologic factors probably are responsible for the scarcity of bryozoans in the middle Paleozoic of the State. Under the circumstances, it seems more likely to me that the collection came from the Permian than from older rocks. From discussing your problem with Tom Dutro, I gather that such an interpretation should obviate your dilemma.

Although the material is very poorly preserved, I am having it cataloged and placed in our stratigraphic collections in order to preserve the little evidence we have for dating.

These brachiopods strengthen the assignment of the bryozoans to RHOMBOTRYPELLA (see Duncans report of 6/15/67).

I have also re-examined 66AHx246 (USGS 22842-PC) and suggest that the other rhynchonelloid reported in my letter of 5/19/67 is probably SEPTACAMERA. The association is, therefore, even more strongly suggestive of a Permian age.

Concerning Permian in the Glacier Bay area, the collection 66AHx115 is definitely Permian as I reported last year (report on shipment A-75-7 dated 2/28/75, copy enclosed).

As you can see, the common tie among these three collections is SEPTACAMERA, and there can be no doubt about the identifications in 66AHx115. I do not know the precise geographic relationships, but from your map in PP 632, there does not appear to be more than about .25 miles separating them.

Consequently, it is reasonable to assign all three collections to the Permian, most likely with a late Leonardian (Antinskian) age.

The collection is being retained.