Page:The plains of Long Island.djvu/5

 peculiar and distinct. It is proper I should state, that my explorations were chiefly limited to the slope extending from the ridge to the ocean on the south, and to the western portion of the island. This range embraces that section of the territory to which my investigations were particularly directed, and afforded me, in the cultivated districts, the data I required for contrasting the soil of the plains with the fertile farms.

—The geological structure of Long Island discloses a remarkable similarity throughout its whole extent, which is rarely if ever found in an equal area of territory. The ingredients of the soil, in every section that I have been able to examine, and the same fact, I was assured on the most reliable authority, exists in every part of the island, exhibits the most singular uniformity. In these respects, and in most of its physical features, Long Island presents a peculiar arrangement that has no analogy to any other district within my knowledge, and indeed distinguishes it from all others. That it is alluvial, and of recent formation, there exists every proof. In my personal explorations, I saw no rocks in site, but perceive that geological authors refer to their appearance near Hurlgate and at Hallett's Cove. These doubtless reveal the croppings-out of the rock of the adjacent mainland. Huge boulders are scattered copiously in the soil at Brooklyn, and in other localities, but upon the plains scarcely a stone occurs over the size of a large pebble. The basis of the entire island appears to be a formation of large pebbles, worn and rounded by attrition. On this foundation reposes a substratum of small pebbles mingled with the superficial soil. Above this substratum occurs the soil of the island, ranging in depth from one foot to three feet, and it is a singular circumstance, which marks the anomalous arrangement of the whole island, that unlike every other territory, the soil is the thinnest and least fertile in depressions, than upon the elevated parts of the surface. The elements of this surface soil are as nearly as possible identical in every part of the island, but varying to some extent in its combinations. In some districts, where clay predominates, it may be termed a clayey-loam; in others, silex is the most conspicuous ingredient, when the soil becomes a sandy-loam. In some limited sections of the island, localities of pure sand are found, but through the center of the island, and particularly on the plains, I saw no appearance of a soil of that character. The greatest prevalence of sand, and the lightest soil I examined, was on the north side of the ridge, in the town of Smithtown; and the next, most assimilating to this, was in the Happaugh valley, in the same town. Both of these localities are upon farms which have been cultivated for generations.

The submergence of the island at some period is demonstrated by numerous circumstances. The gravel formation I have just alluded to, is a sufficient proof. Mr. Thompson, the historian, speaks of fossil remains being exhumed in digging wells, and the marine shell, discovered in the beds of the "Dry rivers," can be traced to no other cause. Possibly the foundations of the island may have been upheaved by some natural convulsion, but I have not scope to pursue this enquiry, and can only assume