GREEN SAND. New Jersey marl. One of the upper secondary deposits of geologists, con sisting, for the most part, of a sandy formation, the grains of which are, however, much softer than those of common sand, and consist of sili cate of iron chiefly; they are of several colors, from greenish gray to deep green and olive. It is extensively developed in the United States, being found in the valley of the Connecticut, southeastern portion of New Jersey, Delaware, and Virginia. Some portions of this deposit contain from seven to twelve per cent. of potash combined with silicate of iron. This is particu larly the case with that in Monmouth and Burlington counties, N. J., and Newcastle county, Del. Numerous pits are therefore, opened for the purpose of reaching this deposit, called Marl, which has been found, in many in stances, to produce remarkable fertility when applied at the rate of 200 to 400 bushels on stiff clayey lands. In selecting specimens, we are to examine the amouut of green sands in it, the fer tility depending upon them; for the clay, com mon sand, and other impurities are of little im portance. The richest kinds are of a deep green
internally, sometimes with an olive tint, but the exterior becomes grayish and covered with a slight efflorescence; it is also readily crushed. The following analysis of a specimen from Mon mouth county will give the particulars of its composition per cent. : Silica 50.00 Alumina 7.00 Protoidde of iron, 22.00 Potash 11.00 Lime 1.00 Magnesia a trace Water 9.00 100.00 The potash here is combined with silica, but their union is readily destroyed by the carbonic acid of the soil, which rapidly forms carbonate of potash. This manure is peculiarly applicable to grass, oats, wheat, corn, and the Cerealia gen erally; it will also be serviceable to roots growing on a stiffish soil. It may not, however, pay the expenses of long transportation, a small quantity of ashes replacing it in the compost heap, and is little used except when near at hand.