W. Prescott on a new species of Chiton. 185 
At Montarville, the shales of the Hudson river formation are 
altered in the vicinity of the dolerite which forms the mass of 
the mountain. Some portions of the strata are very fine-grained, 
reddish-brown, and have an earthy sub-conchoidal fracture, with 
occasional cleavage joints. The hardness of this rock is not 
hism. (This Journal, [2 , XXXV1 : 
2 With pda ts of local metamorphism I conclude 
the present paper, proposing however to give in a subsequent 
one the results of some investigations of certain indigenous 
crystalline rocks. 
Montreal, March 15, 1864. 
—a 
Art, XVI.— Description of a new species of Chiton; by WILLIAM 
Prescorr, M.D., of Concord, N. H. 
When found, to have been of a uniform brilliant red: but now, 
the most prominent portion of the dorsal surface, (which would 
Am. Jour. $c1.—Szconp Series, Vou. XXXVIII, No. 113.—Serr., 
24 
