i6 On the Serpentine Rocks of Hoboken, N. J. &. 
These coals will no doubt prove the cheapest, most du- 
rable, cleanly, and pleasant fuel for warming apartments, as 
well as for many other useful purposes.—They are without 
doubt the best for making edge tools. 
. I believe that Lehigh Coal at 5s. per bushel is as cheap 
as Virginia at 2s. 9d.—In a grate or stove, a fire of this coal 
will Jast from twelve to fourteen hours. 
OLIVER EVANS. 
Arr. [i.— Observations on the Serpentine rocks of Hoboken, 
in New-Jersey, and on the minerals which they contain ; 
by Tuomas Norra.u. 
{Read in the Academy of Natural Sciences of Philadelphia, May 8th, 1821. 
Forwarded in MS. for insertion in this Journal. 
Tus formation which appertains rather to the transition 
than the primitive range, and to the species of serpentine 
called the common kind, occurs at this place in a consid- 
erable mountain mass, which is washed by the tides of the 
Hudson. By its position it appears to be incumbent on the 
granite on which the city of New-York is founded, and in 
contiguity with a rock, sometimes coarsely granular, formed 
principally of quartz and felspar. Seams of breccia formed 
of angular fragments cemented together by a calcareous 
spar resembling arragonite, and which has been erroneous- 
ly announced as a carbonate of magnesia, indicate at least 
the partial transition of this serpentine into the surrounding 
formations, or the transfusion of some foreign ingredient in- 
to the rocky mass while yet yielding and capable of easy 
penetration. 
This serpentine, which differs so much in external char- 
acter from the finer diaphanous or nephritic kind of Massa- 
chusetts, is of an uniform consistence, of an earthy fracture, 
perfect opacity, soft enough to be easily scraped by a knife, 
and of a dull yellowish-green colour, somewhat inclining to 
olive. Its specific gravity by Nicholson’s balance was 
2,820. It acquires but a feeble polish, and is commonly 
penetrated by octahedral crystals, said without sufficient 
authority to be chromated iron. Before the blowpipe it 
remains infusible, and by strong calcination looses 16 per 
