138 
[Assembly 
in some places there are local deposits of clay and loam interstrati- 
fied, which are basin-shaped, and contain the water. These are more 
abundant in the hilly regions than in the plains. Springs are as abundant 
and copious on the south side of the island as on the north, but they break 
out at some distance from the shore, in consequence of the land declin- 
ing almost insensibly from the hills. The great plain of Long Island 
extends from the base of the hills south to the ocean, descending but a few 
feet to a mile. On Hempstead plains the wells are dug from 60 to 120 
feet deep, through beds of gravel and sand, before water is reached, 
which is a little above the level of the ocean. The wells gradually de- 
crease in depth thence to the shore. On most of the farms in the inte- 
rior, artificial means are resorted to, to procure a supply of water for 
cattle and other farm stock. A basin- shaped excavation is made in the 
soil, and puddled with clay, and into this the surface waters are conducted 
during rains. They are called watering-holes, and are a striking feature 
of the farming economy of the island. 
Fossil shells and lignite are not unfrequently found in digging wells 
in the chain of hills which extends through the island.* Such facts 
should be preserved, as they may lead not only to important scientific 
trnths, but to practical results applicable to agriculture. It is well 
known that most of the valuable marls contain fossil shells and charred 
wood or lignite. The observation of such facts may lead to the deve- 
lopment of rich marl beds, and these might be of inestimable value to 
the agricultural interests. Clay beds, similar in character, (and con- 
tained minerals, viz, lignite and pyrites) to that which overlies the 
green marls of New- Jersey, have been observed on West Neck in Suf- 
folk county, and at Rossville in Richmond county. It is not consider- 
ed improbable, that similar marls may be found connected with the same 
series of strata, as in New- Jersey. 
Gneiss. 
No rock was seen in place on Long Island, except at Hurlgate, Hal- 
lett's Cove, and a few localities along the shore within a mile or two of 
these places. The rocks are gneiss, hornblendic gneiss, and hornblende 
slate. The strata are nearly vertical, and range N. 20° E. and S. 20^ 
W. The hornblendic gneiss and gneiss are quarried at Hallett's Cove, 
and are used for basement walls. It is easily dressed with the hammer, 
and is durable, and unchanged by atmospheric causes. 
* Dr. Pierce observed lignite on the west part of Staten Island in 1818, vide Am. Jour. Sci- 
ence 1, p. 146, and Dr. Beck describes it as occurring at Rossville: vide 1st An. Report of the 
Geol. Survey, N. Y. p. 59. 
/ 
