144 ~—- Native Crystallized Carbonate of Magnesia. 
continued chain, which, on the eastern and southern sides, 13 
very steep, but not precipitous ; it gradually declines to the 
west and north, and, in some places, it presents on its summit 
iable 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- 
dive. 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 is4 
greenish yellow; it is brittle, very adhesive to the tongue, 
put little unctuous, and probably contains more alumine and 
_ tess magnesia than steatites in general. Much of it decom- 
_ poses when exposed to air and moisture, and forms 28 
mould, whenever the descent of ground permits an aceumula- 
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 if 
agriculture. 
The minerals observed on the surface of the north-east pat 
of this chain of hills are, secondary greenstone, asbestolt 
sandstone, granite, and gneiss, sparingly scattered in rollet 
masses. In addition to these rocks, in the middle and west: 
ern part of the chain, a mineral of uncommon appearance 
observed. Itis composed principally of quartz, rough, with 
numerous cells of various forms, in which small siliceous ¢tY* 
tals are generally found: the veins or plates of quartz that 
intersect each other, often embrace talc and oxide of iro, 
which, decomposing, gives some specimens the appearance 
volcanic origin. Associated with this cellular ferrugino’® 
quartz, brown heematite is often observed ; this valuable °° 
often yields eighty per cent. of iron of best quality; i 
assume a variety of shapes; they were observed at 
Island, straight and curved, radiating from a centre, 4B 
