v5
““Gasteropoda.

Mangelia ? sp. undt. One worn specimen.

Nassa, sp. Unlike any of the living species on the N.W. coast.

Lunatia ? sp. Test exfoliated.

Trochita, or Galerus. Test exfoliated.

Crypta adunca, Sby. One specimen; undistinguishable from the living
species. Mr. Gabb (Pal. Cal. vol. 2, p. 82,) says that this shell
occurs in the Pliocene and Post Pliocene of California.

Lamellibranchiata.

Solen, sp. One fragment of a large species.

Siliqua—Possibly the young of S. patula, Dixon. Two examples.

Standella—Very like S. planulata, Con., and S. falcata Gld., but smaller
than either.
Several specimens.

Macoma nasuta, Conrad. Two or three specimens. According to Gabb.
(Pal. Cal. vol. 2, p. 93) this recent species occurs also in the
Upper Miocene, Pliocene, and Post Pliocene of California.

Mercenaria—Mr. W. H. Dall thinks this shell is closely related to his
M. Kennicotti, from Alaska.

Chione, sp. undt. Two specimens.

Tapes staminea, Conrad. The most abundant shell in the collection.
It is abundant, in a living state, on the N.W. coast, and Mr.
Gabb says that in California it is found in the Post Pliocene,
Pliocene, and Miocene.

Saxodomus, species undistinguishable. The outer layer of all the speci-
mens, which are not numerous, is entirely exfoliated.

Cardium, one exfoliated valve. Appears to resemble C. Islandicum.

Cardium. Several valves of a species, which may be referable to C.
blandum, Gld.

Arca microdonta, Conrad. An extinct species, found so far only in the
Miocene and Pliocene of California. Two specimens.
Axinaea. Possibly a form of A. patula, Conrad, but barely distinguishable
from the smooth form (var. subobsoleta Carpenter) of the living
A. septentrionalis, Middendorf, of the N.W. coast. Four single

valves.”

From this list it would appear that the Skonun formation

is either Miocene or Pliocene in age. Arnold and Hannibal?
correlate the Skonun sediments with the Empire formation, of
middle Miocene age.

1 Proc. Am. Phil. Soc. vol. LII, 1913, p. 592

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