The Pleistocene of North America: and its vertebrated animals from the states east of the Mississippi River and from the Canadian provinces east of longitude 95°Hay, Oliver Perry
Science
The Pleistocene of North America: and its vertebrated animals from the states east of the Mississippi River and from the Canadian provinces east of longitude 95°
Hay, Oliver Perry
Paleontology -- North America; Paleontology -- Pleistocene; Vertebrates, Fossil
11. _Jeffries Reef, off Portsmouth._—The specimen from this place
consists of the greater part of the left side of the skull of a large
individual. The occipital and the exoccipitals are missing. The bone and
especially the tusk have suffered some decay. The fragment is labeled as
having been dredged from a depth of 50 to 75 fathoms on Eastern Jeffries
Reef. The bottom was hard. Jeffries Reef lies 5 or more miles off the
southernmost part of the Maine coast and extends from the Isle of Shoals
to Boon Island. The skull belonged to an old individual. The length from
the rear of the mastoid process to the front of the premaxilla is 360
mm. The exserted part of the tusk measures 225 mm. in length. At its
base the diameters are 65 mm. and 42 mm. There are 4 large grinding
teeth. There is no reason for supposing that the species represented is
not _O. rosmarus_.
MASSACHUSETTS.
12. _Gay Head, Martha’s Vineyard._—In his “Travels in North America,”
volume I, 1845, page 257, plate V, figure 1, Lyell announced the finding
of a part of a skull of a walrus at Gay Head. This he had purchased from
a fisherman who lived there and who said it had fallen out of a
conglomerate found at that place and which contains bones of cetaceans.
The skull retained but a small portion of its animal matter. Richard
Owen, to whom the skull was shown, regarded it as belonging to a species
distinct from _O. rosmarus_. The upper jaw contained the base of one
tusk, the socket for the other, and 3 molar teeth on each side. The
reduced number of molars furnishes no distinctive character, for
existing individuals sometimes present this number. The base of the tusk
has its transverse diameter greater than usual relatively to the
fore-and-aft diameter. According to Lyell’s illustration of the
specimen, the greater diameter was 70 mm., the shorter 53 mm. The writer
has seen no tusk of _O. rosmarus_ as thick as this; but the thickness is
variable and may possibly attain to two-thirds of the greater diameter.
Inasmuch as the Tertiary deposits at Gay Head, rising above the sea to a
height of about 150 feet, are capped by a sheet of glacial drift and
clays, it is probable that the skull in question had fallen from some of
these drift deposits. According to Professor J. B. Woodworth (17th Ann.
Rept. U. S. Geol. Surv., pt. I, p. 982), there are at Gay Head deposits
of drift which represent some of the older glacial stages as well as the
last one, the Wisconsin. It is possible, therefore, that this walrus
lived there as far back as the middle of the glacial epoch or even
earlier. For additional information on the geology of that island
consult Woodworth’s paper, in which the literature is cited; also the
important paper by N. S. Shaler (7th Ann. Rept. U. S. Geol. Surv., 1888,
pp. 303–363.)
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