0. C. Marsh on a new species of Gavial from New Jersey. 97 
cleavage lines of mica; nor have they the perfect elasticity of 
a true mica. The ey show no tendency to farther exfoliation 
when heated; before the blow-pipe they melt with difficulty 
on the edges into a colorless glass. Profi DesCloizeaux was 
kind enough to examine some of these scales optically; and 
found them to be uniaxial, from whence it is probable that 
they belong to a species biotite. 
e solution in aqua regia afforded the following result in 
reference to 100 parts of the dissolved material. 
‘Spaerire 14:00 
Magnesi 13°68 
Peed: of iron_- 32°00 
Silica 24°00 
No search was made for alkalies ; but from the result obtained 
it is apparent that the magnesia in part explains the use made 
b ee meas of this material for a fertilizer, as described by 
r. Adam 
The pein, however, which most interested me was the dis- 
covery thus accidentally made of the cause of the worm-like 
exfoliation in the mineral, viz: from the coating of the mica 
scales with a hydrated, argillaceous mixture, which probably 
owes its origin to the decomposition of some other _ of the 
micaceous or chloritic family. In subjecting a fragment of the 
vermiculite of Millbury, Mass., to a similar action of aqua re; 
the result was an abundanée of brilliant green scales, O batle 
belonging to the species ripidolite. It may therefore be sug- 
gested, that many earthy species of minerals (silicates) will under 
analogous treatment be found to be less homogeneous than 
been suppose 
Amberst, May 7, 1870. 
T. XUIL—WNotice of a new : of Gavial from the Eocene 
of New Jersey; by Professor QO. C. gees of Yale College. 
and ten vertebre. The o odssification of the neural arches of 
the vertebra, and the ene entire obliteration in some of them 
of the sutures, would imply that fous individual, although 
diminutive, was nearly or quite ma 
Am. Jour. So1.—Szconp Szrrss, Vou. L, ee i 148, —JULY, 1870. 
7 
