Summary

These collections contain the first undoubted marine Eocene from the Alaska Peninsula; it is found on the east side of Pavlof Bay and on Korovin Island. These oldest Tertiary rocks are of middle Eocene age. Previously the oldest rocks known (late Eocene or early Oligocene) were in the vicinity of Mud Bay off Port Moller. The supposed Eocene rocks of Palache, Atwood, and Dall are of middle Oligocene age, the olderst possibly early Oligocene.

The Eocene faunas are closely related to those of Washington and Oregon and probably can be considered as part of the same distributional range.

The Oligocene faunas, on the other hand, are dominantly Asiatic, a condition that extends eastward to equivalent parts of the Katalla and Poul Creek formations (I regard the lower part of the Poul Creek as Lincoln). How much admixture of Asiatic and American species there is in the Katalla and Yakataga districts has not been fully checked since this condition was realized, but in the Alaskan Peninsula the few species that range southward on the American side also range to Asia and the remainder of the fauna consists of species described from Honshu, Hokkaido, Sakhalin, Kamchatka, and Koryak.

Whether the Blakely stage (late Oligocene and early Miocene) is represented is uncertain. I have regarded beds near Left Head Bay as Blakely. However, the Coal Bay section of this report appears to be the same zone and according to field evidence it falls below beds I regard as Lincoln equivalent.

The type Unga formation of Dall is represented by the Mytilus middendorffi-bearing rock from Port Moller. This is the oldest Miocene horizon if there is no Blakely present. Both the Unga and beds near Bear Lake (probably Late Miocene) have American affinities, little or no Asiatic influence being noted.

Except where are noted as brackish or freshwater, these faunas are moderately shallow marine. I would like to have a generalized section on which these localities are plotted in their stratigraphic position.

These collections are undoubtedly Eocene and probably middle Eocene. With the exception of some beds near Mud Bay that appear to be late Eocene or early Oligocene, this is the first good Eocene and the oldest Tertiary from the Alaskan Peninsula. The Tolstoi horizon is definitely older than the Mud Bay horizon. All of the colections of Palache and Atwood which at one time were referred to the Eocene are of middle Oligocene age.

Age: Eocene