144 Native Crystallized Carbonate of Magnesia. 



continued chain, which, on the eastern and southern sides, is 

 very steep, but not precipitous ; it gradually declines to the 

 west and north, and, in some places, it presents on its summit 

 table land of considerable extent. A prominent ridge crosses 

 the island, connecting the elevated ground of the south, with 

 the hills of the northern part. A species of steatite, contain- 

 ing veins of common, indurated, and scaly talc, amianthus, 

 and most of the varieties of asbestus, and some chromate of 

 iron, constitutes the nucleus of the whole mountain range and 

 elevated ground of the eastern division, stamping it as primi- 

 tive. This steatite approaches, in most places, within a foot 

 and a half of the surface, and appears in small angular loose 

 blocks, wherever the soil has been removed. Its colour is a 

 greenish yellow ; it is brittle, very adhesive to the tongue, 

 but little unctuous, and probably contains more alumine and 

 less magnesia than steatites in general. Much of it decom- 

 poses when exposed to air and moisture, and forms a good 

 mould, whenever the descent of ground permits an accumula- 

 tion of earth. It is not improbable, that in most places of the 

 Staten-Island hills, when magnesia constitutes a considerable 

 ingredient of the rock, it will be found saturated with carbonic 

 acid, obviating the objection to common magnesian minerals in 

 agriculture. 



The minerals observed on the surface of the northeast part 

 of this chain of hills are, secondary greenstone, asbestoid, 

 sandstone, granite, and gneiss, sparingly scattered in rolled 

 masses. In addition to these rocks, in the middle and west' 

 ern part of the chain, a mineral of uncommon appearance is 

 observed. It is composed principally of quartz, rough, with 

 numerous cells of various forms, in which small siliceous crys- 

 tals are generally found : the veins or plates of quartz that 

 intersect each other, often embrace talc and oxide of iron, 

 which, decomposing, gives some specimens the appearance of 

 volcanic origin. Associated with this cellular ferruginous 

 quartz, brown haematite is often observed ; this valuable ore 

 often yields eighty per cent, of iron of best quality ; its fibres 

 assume a variety of shapes ; they were observed at Staten- 

 Island, straight and ctiTved. radiating from a centre, and exhi- 



