relations of the Metamorphic Rocks. 225 
abound, and, under the influence of metamorphism, sometimes 
develop crystalline orthoclase. At other times, re are conver- 
ted into a soft micaceous mineral and form a kind of mica-schist. 
Chiastolite and staurotide are never met with in the schists of 
set series, at least in its northern portions, throughout Canada 
New England. The anorthosites of the Labrador series are 
arian by fine grained diorites, in which the feldspar varies 
from albite to very basic varieties, which are sometimes associ- 
ated with an aluminous mineral allied to chlorite in composition. 
Chioritic schists, frequently accompanied by epidote, abound in 
this serie es. e great predomi nance 0 magnesia in the 
In some “parts of this series, pure limestones occur, which contd 
various crystalline minerals common also to the Laurentian lime- 
Stones, and to ‘those of the fourth series. The only graphite 
which has been foanast in the third series is in the form of impure 
plumbaginous shal 
and fourth series are contiguous! aliegag! =. heir: extent, so sp 
4s examined, but are everywhere separated from the Laurentian 
and brador series by a zone of unaltered Paleozoic rocks. 
nasses ot intrusive granite occur among the crystalline 
strata of the fourth series, but are rare or unknown among the 
Am. Jour. Scr—Szcosp Sextus, VoL. XXXVI, No. 107.—Sepr., 1863. 
29 . 
