176 
GEOLOGY OF THE FIRST DISTRICT. 
The materials just mentioned also constitute the mass of the hills from Jamaica to Williams- 
town and Brooklyn. The excavations at Williamstown, and the stone fences for six miles 
towards Jamaica, show the boulders to great advantage. 
At Brooklyn, on the heights back of the Navy Yard, where extensive excavations were 
being made for grading streets in 1837, the boulders imbedded in gravel and loam were 
observed to consist mostly of greenstone, from a highly crystalline to a perfectly compact fine¬ 
grained texture. Granite, gneiss, and red sandstone boulders and blocks were common. 
The boulders and blocks are often large masses, from five to twenty or more tons weight, 
lying on and surrounded by loam or sandy gravel. Some of the boulders showed “diluvial” 
scratches. 
The upper soil at Brooklyn is generally a yellowish sand and sandy loam ; below is a loam 
and gravel, containing great numbers of boulders, blocks and pebbles. Below the boulder 
bed is a series of strata of sand, gravel and clay, in which shells are said to be frequently 
found, but I saw none. Some of the streets that were being graded, were twenty to fifty feet 
in some places below the original surface of the earth, and exposed to view fine sections of 
the strata. Greenstone, serpentine, red sandstone, granite, gneiss, etc. form the mass of the 
gravel and boulder beds. 
Between Flatbush and Brooklyn, the country is sandy gravel and sandy loam, like all the 
great southern plain of Long island to the base of the hills. Soon after beginning to ascend 
the hills. Prof. Merrick found some small fragments of shells in a gravel bank, where exca¬ 
vations had been made for sand. It was in the woods, near the tavern, at the head of the 
road. The fragments w^ere very small and water-worn, and too imperfect to determine their 
species. From thence to Brooklyn, the surface was loam and pebbles, containing great num¬ 
bers of boulders, which were principally greenstone. 
Between Jamaica and Brooklyn, on the line of the railroad, the excavations show the soil 
of the plain to consist of sand and gravel, in some places rather loamy, usually of a light yel¬ 
lowish color, from the intermixture of the hydrated peroxide of iron. A little west of East 
New-York (a paper city five miles east of Brooklyn), the railroad enters the range of hills, 
and is excavated for a considerable distance from ten to thirty feet. The materials excavated 
consist of loam and “ hardpan,” containing multitudes of boulders, blocks, and pebbles of 
greenstone, granite, hornblende rock, gneiss, red sandstone and serpentine. The same cha¬ 
racters of soil and boulders continue to Brooklyn. 
The hilly region from Brooklyn to Bedford, and thence to Flatbush and Bath, are similar 
to that described, as also the plains of Flatbush, like the rest of the great plains of Long 
island. About one mile west of Bath, in New-Utrecht, boulders of greenstone are very 
abundant, with some black serpentine and red sandstone ; and these, with a heavy loam and 
some gravel, form the soil of the country around. This place is where the range of hills of 
Long island is intersected by the shore. This range of hills is nearly straight in its general 
direction to Flushing and Newtown, where it curves around by Williamsburgh and Brooklyn, 
to Fort Hamilton and Fort La Fayette, at the Narrows; and the same range of hills is con- 
