54 Pierce on Amianthus and Carbonate of Magnesia. 
Arr. IV. Carbonate of Magnesia, and very uncommor . 
Amianthus, discovered near New-York.—Extract of a letter 
_ from Mr. James Pierce to the Editor. 
New-York, May 18, 1818. 
DEAR SIR, 
I FORWARD you specimens of straw and rose-coloured 
amianthus I recently met with on Staten-Island, which I de- 
tached, in strips, from a rock ; it not appearing, as is usual, in 
veins. It breaks up like flax, and may be spun and woven 
ithout the aid of moisture ; and, in respect to tenacity, flexi- 
bility, and length of fibre, it may be considered the best found 
in this country, and perhaps equal to any hitherto discovered. 
Staten-Island exhibits many minerals worthy of examination. — 
I subjoin, as requested, the following geological descrip- 
tion, &c. / 
Hoboken, where I discovered native carbonate of magnesia, 
is situated opposite the city of New-York, on the western or 
New-Jersey bank of the Hudson. It is a primitive, insulated 
elevation, with a nucleus of serpentine; the ground gradually — 
descends in every direction except on the river side, where — 
mural precipices of serpentine rock are observed, extending 
about 100 rods parallel with the water, and elevated from 60 
to 100 feet above its level. The carbonate of magnesia I found 
in horizontal veins of near two inches in breadth, and of un- 
known depth, in a midway region of this serpentine ledge; 1 
extracted a considerable quantity with a spoon. When first 
taken out it was soft, white, and very slightly adhesive, from # 
little moisture; but, when dry, fell to powder without fric- 
tion. The nature of the mineral I conjectured as soon a 
seen, and treated it with diluted sulphuric acid, in which it 
ent. ely dissolved with efferyescence, forming a bitter fluid, 
and leaving no sediment. Upon evaporation, well defined 
crystals of Epsom salts were formed. It differs little from the 
manufactured carbonate of magnesia of the shops; but 
rather a super than a sub-carbonate. It has been analyzed by 
