AD, THE FLORA OF THE AMBOY CLAYS. 
portion of Brooklyn and the adjacent shores of Hell Gate. Eastward of 
this the Amboy Clays are generally covered with drift, but they reappear 
at Glen Cove, Sea Cliff, and various other points on the north shore of 
Long Island, where it has been deeply cut into by glacial action and is 
now occupied by inlets from Long Island Sound. Possibly the whole 
length of Long Island is underlain by the Amboy Clays, as characteristic 
fossils have been found in the moraine on the extreme end of Montauk 
Point. Farther east, the clay series reappears on Marthas Vineyard and 
forms part of the noted cliff of Gay Head. Again interrupted by the 
waters of the ocean, it apparently reappears in the southern counties of 
Massachusetts, and it was described by Prof. Edward Hitchcock in the 
reports of the geological survey of Massachusetts, though its geological 
equivalents were not recognized. 
The southern extension of the formation has not been definitely traced, 
but it apparently thins out southward, appearing as an insignificant element 
in the series in Cecil County, Md., where Professor Uhler has described it 
as the bed of “alternate sands and clays” which there rests on the Potomac 
and is overlain by the equivalents of the Cretaceous marl beds of New 
Jersey. South of this point it has not been recognized. 
In New Jersey the Amboy Clay series is generally underlain by the 
Triassic red sandstones, which have been proved to be of the age of 
the Keuper or Upper Trias in Europe. 
The Amboy Clays are for the most part an estuary deposit. This is 
indicated by the presence of brackish-water shells, Corbicula, Gnathodon, 
ete., described by Prof. R. P. Whitfield in his report on the Brachiopoda 
and Lamellibranchiata of the Raritan Clays and Greensand Marls of New 
Jersey, which forms Vol. I of the Report of the Geological Survey of 
that State,’ made under the direction of Prof. George H. Cook. Near the 
top of the series, however, marine shells occur in the vicinity of Keyport, 
N. J., such as Inoceramus, Pholadomya, ete., found in the greensands 
above.” This evidence shows that the New Jersey clays occupy a position 
' This is a part of the edition of Vol. IX, Monographs of the U. 8. Geol. Survey, Washington, 1885, 
issued by the Geological Survey of New Jersey, with a separate title page of later date (1886). 
*Since this was written the occurrence of a marine mollusean fauna associated with the charac- 
teristic flora of the Amboy Clays, in drift material, has also been noted by me on Staten Island (Trans, 
N. Y. Acad. Sci., Vol. XI, pp. 96-104, February, 1892).—A. H. 
