162 CotKjlomerates iiiGtieissic Terranes — A.Winchell. 
crystalline honibleade with some feldspar, and which are proba- 
bly pebbles transmuted."* 
At Granby, in Vermont, "the pebbles, manifestly rounded^ 
are either mica schist or white, almost hyaline, quartz * * * 
and the base is a fine-grained syenite, passing sometimes almost 
into mica schist." "When the pebbles are highly crystallized^ 
they become so incorporated with the matrix that it is difficult 
to separate them with a smooth surface; and, if we are not mis- 
taken, they pass insensibly into those rounded nodules chiefly 
hornblendic (augitic?) so common in syenite, especially that of 
Ascutney. We think those are produced from the metamor- 
phosis of pebbles which have become crystalline since they were 
formed into conglomerate. « ♦ * These facts certainly give 
great plausibility to the view which supposes granite and syenite 
to be often the results of the metamorphosis of stratified rocks."t 
At the meeting of the American Association at Springfield, 
in 1859, Professor Hubbard, of Dartmouth College, exhibited a 
specimen of pure white granite from Warren, New Hampshire, 
in which there lay imbedded a rounded bowlder of hornblende 
rock more than a foot in diameter, and easily separable from the 
granite. J 
Dr. G. A. Hawes, in 1878,§ recorded some mica sheets at P^ast 
Hanover, New Hampshire, which are "mottled by what are ap- 
parently pebbles of various sorts and sizes, that have been 
flattened out between the layers." He recognizes the evidences 
of their former plasticity and of their metamorphism, even 
when not carried to such a degree as to entirely obliterate all 
signs of the original constitution of the sedimentary mass. 
None of the examples cited from America possess evidence of 
such strength as that afforded by the Saganaga gneiss in refer- 
ence to the former fragmeutal condition of the oldest crystalline 
rocks. The Saganaga gneiss is massive, insomuch that it is gen- 
* Compare the black pebbles in the Saganaga syenite before mentioned 
and set down as apparently augitic ; and my independent suggestion that 
they are the products of metamorphic action. 
t The views of Dr. Charles T. Jackson on this question may be found in 
Proc. Bos. Soc. Naf. His., 1860. Professor W. B. Kogers' views are found 
in same, 1861, cited in Am. Jour. Set., II, xxxi, 440-2, May, 1801. 
X Geology of Vermont, p. 44. Dr. Hitchcock enumerates other localities 
of occurrence of conglomerates with flattened pebbles, in Bernardston, 
Mass., where the matrix is a mica schist. The same is true at Bellingham, 
Mass. These features are still more decided in bowlders near Northampton.. 
§ Hawes in Geology of New HampHhire, vol. iii, pt. iv, p. 220. 
