86 
AMERICAN GEOLOGY. 
agatized bands, with a shape more oval than round, as in fig. 
When serpentine is intermixed with limestone, it is often 
rich in other minerals. The primary limestone, though mixed 
with serpentine, is frequently pure; sometimes it is magnesian. 
That of Jefferson county is composed of 
Carbonate of lime, 98‘24 
Alumina and peroxide of iron, O^S 
Silica, 0’88 
The defects of this serpentine limestone, arise from an inter¬ 
mixture of silica, pyroxene, and hornblende, which appear in 
masses disseminated through it. 
A serpentine of a pattern somewhat different * from the fore¬ 
going, occurs in the state of Connecticut, at Milford. It has 
been described in the Geological Report of that state, by Mr. 
Percival, as a serpentine marble. It consists of two short 
ranges; the one includes the New Haven quarries, and the other 
the Milford. The rock is remarkably fine-grained, and is dis¬ 
tinguished for the beauty of its variegated colors; blue, green 
and yellowish green predominating. Pyroxene, epidote, mag¬ 
netic iron, picrolite, and chromic iron, are associated with it. 
The serpentine marble of Milford and New Haven, is more 
intimately blended with the limestone than that of northern 
