M.EMBEKS OF THE PVROCRVSTALLtNE CLASS. 
67 
large beds of granite in Maine, and other parts oi the country. 
We have not as yet discovered granite as new as the cretaceous 
system in this country, while in the Alps this rock penetrates 
the chalk formation. It appears, from observation, that many 
of the most imposing outbursts of granite were accompanied 
with important changes of level of the earth’s surface, and con¬ 
sequently affected more or less animal and vegetable life. 
§ 54. Distribution of granite in the United States. The 
granites of this country furnish the usual varieties which have 
been described by foreign authors. Two of the most common 
departures from the normal kind is composed of quartz and 
feldspar, the mica being absent, and that which is composed of 
quartz, feldspar, and hornblende or pyroxene—the two re¬ 
placing the mica. Whatever change the rock has undergone, 
it retains the massive structure of granite. A less common 
variety receives talc in the place of mica, and is called proto¬ 
gene, and forms that kind which is liable to decomposition, 
and which furnishes one of the porcelain clays. The soda 
granite at Gouverneur contains large crystalline masses of albite, 
though frequently in perfect hemitrope crystals, associated 
with carbonate of lime. 
§ 55. Granites of northern JVeio York. In northern New 
York the granites are exceedingly variable in composition. In 
this district they become metalliferous, and in this respect differ 
from those of New England. In Clinton county a flesh-colored 
granite is traversed by lodes of magnetic iron. The state 
prison, located in that county, is built upon lodes of this 
rock. The magnetic iron of Arnold hill, in the same county, 
is in the same rock. One vein of this hill is a peroxide. The 
granite of St. Lawrence county is in part similar to the New 
England granite, particularly that variety which is found at 
Alexandria bay. It forms the Thousand islands of the St. Law¬ 
rence, and contains schorl and imperfect garnets and epidote. 
The most common kind of this county is associated with lime¬ 
stone. It is underlaid and traversed by seams or veins of 
coarse crystallized limestone. The rock itself is also coarser 
