212 J. D. Dana—Geological Relations of the 
exposed for a length of twenty feet. The material shows it to 
be no vein or dike, but a bed from the schist; it is a dark-col- 
ored quartzose garnet rock, heavy with magnetite and contain- 
ing some staurolite, resembling much a portion of the schist in 
section 1 (above described), near the soda- "alpen The cov- 
ering of earth prevented a determination of its whole extent. 
In the same kind o f rock, about fifty yards aa of the brick- 
yard which divides Montrose Point (into a North Montrose 
and a South Montrose Point), a vein-like band, two feet to 
twenty inches wide descends the bluff, which consists of a light- 
gray massive argillyte. Examined in thin slices by the micro- 
scope, it is found to have a mealy aspect with microlitic points, 
like an argillyte in the first stages of metamorphism. The 
band is a bed from ne ip although a different variety of it 
from any expos ou at ‘ 
microscope shows, on an examination of thin slices, that some 
consist of grains of hornblende and feldspar, the latter partly 
orthoclase, and look like hornblende schist, while others are 
1 e of the 
numerous in the noryte of the northern part of the point. 
Figure 4, as stated on page 201, represents an “ inclusion” in 
the noryte ; but the inclusion is evidently a bed bent back on 
itself; for a vein would not be thus folded double in its enclos- 
ing rock. The rock of this bed much resembles the noryte, 
though finer in grain, and consists (as observed by means of a 
thin slice) of hornblende with much augite and some triclinic 
eldspar. 
On the same part of the point, the noryte and chrysolitie 
rocks apparently cut through one another, but with the noryte 
oftener like an inclusion in the chrysolitie ee Again, they 
follow one another, or lie side by side, but without a distinct 
divisional plane ; and in one place the rock consists of bands 
f noryte and chrysolitic poe pen yte without a trace of any 
planes of separation. 
to three inches wide, noryte bands 
(the fine-dotted in the Agnre), 
jae 
chrysolitic rock. Difference ze aa yep io She 
conditions, give rise to such a 
structure, although the bands are so thin; successive outflow- 
ings of different eruptive rocks could not produce it. 
