on the Coast of New England. 137 
The Callista convexa is still found sparingly in shallow, shel- 
tered localities in Casco Bay, and rarely at Eastport, Me., but 
it is more common in the colony of the Gulf of St. Lawrence, 
and very common south of Cape Cod. But the oysters (Ostrea 
Virginiana) and “scollops” (Pecten wradians) had apparently 
become extinct in the vicinity of Portland Harbor before the 
period of the Indian shell-heaps, for neither of these species occur 
in the heaps on the adjacent islands, while the quahogs lin- 
gered on until that time, but have subsequently died out every- 
where in this region, except at Quahog Bay. ‘The oysters have 
survived only in the locality near Damariscotta, though far less 
abundant there than during the Indian period. 
_ The beds of dead shells of oysters, Pectens, etc., were found 
in making excavations in the harbor with mud-digging machines. 
great extent. Mr. C. B. Fuller, who has made a good collection 
of these shells for the Portland Natural History Society, informs 
me that the farmers have, in some instances, found it profitable 
to cart away these ancient shells for fertilizing purposes. The 
position of these beds indicate that no important change in 
the relative level of the land and water can have occurred in 
that region since they were formed. These beds are, of course, 
easily distinguished from the much more ancient Post-Pliocene 
deposits that oceur abundantly in the same region, but extend 
back several miles from the coast, and occur at all levels, from 
low-water mark to about 200 feet above high*water mark. The 
latter are characterized, in that region, by a more arctic assem- 
blage of shells than that now inhabiting the adjacent waters, 
though most of the species still survive, in deep water, off the 
coast of Maine. 
The facts above presented indicate: 1,—that in the Post-Plio- 
probably about like that of the present Newfoundland or Labra- 
dor Coast; 2,—that at a subsequent period, when the coast had 
ture of _these waters has gradually declined, but was still some- 
Water in that part of the gulf, which 
‘ p the sun, in summer; an 
sufficiently powerful to thoroughly mix up the very cold waters 
