456 ADDRESS OF T. STERRY HUNT. 
Laurentian gneiss. The coarse-grained, porphyritic, reddish vari- 
eties common to the latter are wanting in the Green Mountains, 
where the gneiss is generally of pale greenish and grayish hues. 
Massive stratified diorites, and epidotic and chloritic rocks, often 
more or less schistose, with steatite, dark colored serpentines and 
ferriferous dolomites and magnesites also characterize this gneissi¢ 
series, and are intimately associated with beds of iron ore, generally : 
a slaty hematite, but occasionally magnetite. Chrome, titanium, 
nickel, copper, antimony and gold are frequently met with in this se- 
ries. The gneisses often pass into schistose micaceous quartzites, 
and the argillites, which abound, frequently assume a soft, unctuous 
character, which has acquired for them the name of talcose or na- ~ 
creous slates, though analysis shows them not to be magnesian, 
but to consist essentially of a hydrous micaceous mineral. They 
are sometimes black and graphitic. 
Ill. The White Mountain Series. This series is characterized 
by the predominance of well defined mica-schists interstratified 
with micaceous gneisses. ‘These latter are ordinarily light colored 
from the presence of white feldspar, and, though generally fine in 
texture, are sometimes coarse-grained and porphyritic. They are 
` less strong and coherent than the gneisses of the Laurentian, and 
pass, through the predominance of mica, into mica-schists, which 
are themselves more or less tender and friable, and present every 
variety, from a coarse gneiss-like aggregate down to a fine-grained 7 
schist, which passes into argillite. The micaceous schists of this 
series are generally much richer in mica than those of the precet- 
ing series, and often contain a large proportion of well defined crys- 
talline tables belonging to the species muscovite. The cleavage 
of these micaceous schists is generally, if not always, coincident 
with the bedding, but the plates of mica in the coarser-grained ; 
varieties are often arranged at various angles to the cleavage and a 
bedding-plane, showing that they were developed after sedimenta- 
tion, by crystallization in the mass; a circumstance which distin- 
guishes them from rocks derived from the ruins of these, which are 
met with in more recent series. The White Mountain rocks algo 
include beds of micaceous quartzite. The basic silicates in this 
series are represented chiefly by dark colored gneisses and schists, 
in which hornblende takes the place of mica. These pass occ 
sionally into beds of dark hornblende-rock, sometimes holding ee 
garnets. Beds of crystalline limestone occasionally occur in the 2 
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