1831. 57 Trans. N. Y. Ac. Scz. 
hills. This has now (Dec.tst) reached a total depth of 210 feet, and 
the boring is still unfinished. The section thus far has been as follows: 
Prtaei thrifts! o:0).5 See: . . Rs ic. i wt 80 feet. 
Various kinds of tough hornblende schist, apparently 
MArYINS tOcSerpenuMe. goo. . . Fae sete det. 130 feet. 
As yet no gneiss nor granite has been reached. 
An outcrop of clay occurs near Clifton, about three-fourths of a mile 
south of the Forts, near the southern edge of the terminal moraine; it 
has been found, by borings made by Mr. Charles Townsend, in excava- 
tions for cellars, to be at least ten feet in thickness, and of a light color. 
The clay is probably of Cretaceous age, and if so, this is the most 
eastern point at which beds of that age are known on Staten Island. 
Mr. W. T. Davis has recently observed a large fossiliferous boulder 
of Schoharie Grit on the shore at Brighton Point. The fossils have 
Deen submitted to Dr. Newberry, and the following species identified :— 
Dalmanites anchiops; Orthoceras Pelops, Strophodonta hemtspherica , 
Atrypa reticularis; Strophomena rhombotdalis; a Fenestella; and 
Zaphrentis prolifera. 
Glacial groovings have recently been noticed on the hornblende-rock 
which is exposed at tide-level on Brighton Point. Some of the grooves 
are at least one-quarter of an inch in depth, three inches wide and four 
feet long. Their bearing varies from N. 15° W. to N. 17° W. 
DISCUSSION. 
Prof. D. S. MARTIN considered the specimen of so-called hornblende 
schist from the well-boring, not to consist properly of that rock, but to 
be partly hydrated—apparently a less altered condition of the rock 
which higher up gives us the soft, semi-fibrous serpentine of the island. 
Dr. NEWBERRY regarded the serpentine of Staten Island as probably 
a pseudomorphous condition of hornblende slate. It differs consider- 
ably from the mottled serpentine of New York Island, which is ‘ verde 
antique”; that is, is composed partly of serpentine and partly of car- 
bonate of lime, and is scarcely distinguishable from the Moriah marble, 
which is quarried at Moriah, Thurman, etc., in the Adirondack region. 
It is a peculiar rock, and one of the connecting links between the rocks 
of New York Island and those of northern New York and Canada. 
Taken together, these afford strong indications of the Laurentian age 
of the New York Island and Staten Island crystalline rocks. 
Dr. Newberry further said that the accurate determination of the age 
of the rocks of New York Island, of Staten Island, and of those under- 
lying the drift of Long Island, was in the highest degree desirable and 
important ; and while he was satisfied that the former were Laurentian, 
and the latter Cretaceous, it was eminently desirable that unquestion- 
