J. W. Maliet on Schrotterite from Alabama. 79 
In this connection, permit me to ask,—in the abundant ma- 
rine fauna observed by explorers, have we any examples of 
boreal or hyperborean species? Have we not negative proof 
in the absence of all Arctic species, that polar currents did not 
strike upon the Carboniferous shores. Thus we find evidence of 
the pre-existence of a Devonian and Silurian continent, lying 
northwards of the Carboniferous portion, forming a permanently 
separating barrier between the polar and tropical waters, The 
south and southwestern slopes of this continent were in a state 
of oscillation, and upon them were the coal measures laid down 
by tides, currents and other aqueous forces, just as the tertiary 
was added to the cretaceous, or the quarternary to the coasts of 
New Jersey or Long Island. 
Williamsburgh, L. L, April 22, 1858. 
Art. XI.—On Schritterite from Cherokee Co., Alabama; by 
J. W. MALLET. 
late Professor Tuomey has _ 
vonian formation in this region. 
Be 
ance, is dull, nearly opaque, and slightly stained with peroxyd 
of prarrs this est teak extend so far as to form a distinct. 
crust. The mineral when broken closely resembles gum arabic ; 
it is translucent, nearly transparent, and of the lightest possible 
‘brown tint, almost col ed Streak white; lustre vitreous, in- 
clining to resinous; fracture imperfect conchoidal; very brittle. 
Hardness =3°5. Spec. grav. =1074. 
~~ Heated in a glass tube, the mineral gives off water, becomes 
opaque and white, and, when highly heated, of a light lavender- 
