132 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
by a few large feldspars. Although the outline of the patches is 
fairly defined, yet there is perfect gradation without line of separa¬ 
tion at the juncture of the rocks ; hence they are clearly segregations 
and not inclusions. A very similar example is figured by J. 
Arthur Phillips (’80). There is no indication of spheroidal or con¬ 
centric structure often observed in such segregations. Similar differ¬ 
entiations in the granite of Mt. Ktaadn, Maine, are noted by Hamlin 
(’81, p. 212). Some of these had their outlines sharply defined, and 
others merged gradually into the inclosing granite. They are finer 
grained, darker colored and commonly deep gray. Such variations 
are likewise recorded in New Brunswick by Matthew (’94, p. 191) 
and in Maine by Merrill (’83, p. 137). They are probably due 
simply to an abnormal arrangement of the minerals constituting the 
granite, the orthoclase decreasing and dark silicates increasing as the 
rock becomes finer, while the quartz particles alone retain their 
dimensions. In the Wasatch Range in Utah tunnels showed that 
these segregated nests did not extend deeply into the rock, so that 
they may represent the first step in transition from the normal deep- 
seated hornblendic granite to the more rapidly cooled surface por¬ 
phyries, later described, which these dark patches closely resemble. 
Microscopically they present the same minerals as the including 
rock, although they are packed together in smaller pieces, producing 
a finer-grained granitic texture. If anything a little more plagio- 
clase is noticeable. Some of the quartz occurs in large-sized grains. 
Hornblende needles occur as normally, while the dark green silicates 
both mica and hornblende and their alteration products, are much 
more abundant than in the mass of the granite. 
Further south, in Pine Hill, Braintree, the granite assumes a reddish 
or pinkish color, resembling the hornblende granites of Mt. Desert 
Island, Me. (Hitchcock, ’63, p. 271, Shaler, ’89, Davis, ’94, p. 46), 
and at Iron Mountain, Mo. (Pumpelly, ’73, p. 5, ’92, p. 220, and 
Nason, ’92). In both these localities the granite occurs associated 
with like porphyries. This variety is known among the quarrymen 
as the Braintree granite. The feldspars are crystals up to 1 or 
1.5 mm. long and twinned. The reddish color is no doubt due 
to a partial oxidation of the iron, not only in the dark silicates but 
also in the peroxidation of the iron to which the feldspar of the 
unaltered gray granite owes its color ; the gray granite, in the case 
of the Echo quarry on Payne’s Hill, being found only in the deepest 
part of the quarry. In some parts of the red granite the basic 
