320 Scientific Intelligence. 
analysis of which is cited in No. 23; and also, for half of it, as Mr. 
Hawes suggests, to that of common feldspar (orthoclase). The 
slate is peculiar in affording so large a percentage of alkali (7°78), 
and so small of silica; but it varies in its silica, being in some 
laces an “ argillaceous quartzyte ;” in others a "é felsitic slate,” 
weathering w 
This view that the andalusite-slates and Montalban schists 
(which also are often andalusitic) correspond to a stratum higher 
in the series than the Mount Willard dea is sustained by the 
occurrence of masses of them in the of —e nite on Cascade 
rytio % or “spotted” granite named the “ Albany granite,” is stated 
to bound it on the west and to occur e it disappears to the 
north. Whether the ‘ulate dinalppeaee os dipping beneath the 
granite, or by passage into it, is not stated. Th ‘Alb bany granite 
is in the larger part a ranite without cine (p. 143), and hence 
may have nearly the constitution of the slat 
rofessor Hitchcock states that the penphtis granitoid a 
ten to two hundred feet wide, which marks the junction in Mo 
Willard of the andalusite slate and Mount Willard granite, 1 ak 
from which is Mount Willard grits was made, and that from 
which the andalusitic slate proceeded, had some beds of passage ; 
there was a transition in the metamorphic products because of a 
transition in the material and in other conditions. 
e structure of the White Mountains is so exceedingly com- 
plex, that it re reasonably give rise to Heo diverse ah eons 
tions. The view the write has here seems at least to 
be worth ecealbetiiiy’t in the future study of t of the region. 
