T. S. Hunt on Lithology. 265 
{Des Roches, p. 75). In consequence of this confusion, and of 
the vague manner in which the term is used to include rocks 
which are sometimes diorites and sometimes varieties of dolerite 
or basalt, Cotta seems disposed to’ reject the name of melaphyre 
as a useless synonym, in which I agree with him. (Gesteinslehre, 
p.48.) More recently however, Senft (Die Felsarten, p. 268,) has 
endeavored to give a new signification to the term, and defines 
melaphyre as a reddish-gray or greenish-brown colored rock, 
passing into black, and containing neither hornblende nor pyrox- 
ene. The melaphyres of Thuringia and of the Hartz, according 
to him, consist of labradorite with iron-chlorite, (delessite,) car- 
bonates of iron and lime, and a considerable portion of titanifer- 
ous magnetic iron. Hornblende and mica are present only as 
rare and accidental minerals. We have already alluded to this 
class of anorthosite rocks, as requiring a distinctive name, but 
from the historical relations of the word melaphyre, it seems to 
be an unfortunate appellation for rocks which are not black in 
color, and from which both hornblende and pyroxen 
_ ‘ve now come to consider that third group of silicated rocks, 
in which the feldspathides are replaced by the denser double sil- 
lcates of the grenatide family, garnet, epidote, zoisite, and per- 
haps idocrase. Red garnet enters into many gneissic rocks, and 
even forms with a little admixture of quartz, rock masses. In 
some of these, as in the Laurentian series, there appears an ad- 
“Mixture of pyroxene, forming a passage into omphazite or eclo- 
Related to this is an apparently undescribed rock from the Ty- 
Tol, of which a specimen is before me, consisting of red garnet, 
Composed of olivine, with pyroxene, and enstatite, a magnesian 
augite; these minerals bein p : ; 
ilmenite. Thave already alluded to the true euphotides, in which 
2 Compact zoisite, ( jade or saussurite,) takes the place of feldspar 
Ma rock th 
