318 Canadian Record of Science. 



along the shores of Lake Champlain Prof. Kemp has- 

 pointed out the probable occurrence of an area of nephe- 

 line syenite in that region, which has not yet, however^ 

 been discovered, though amongst the many igneous rocks 

 of these localities even a series of such a character may 

 yet be found perhaps running along the western border of 

 the Appalachian folding. 



The other rocks of igneous origin in this vicinity are 

 the well-known serpentines of the Eastern Townships, 

 three miles to the south, which contain irruptive masses 

 of hornblende granite, and are bordered on the south by a 

 volcanic agglomerate, the matrix of which is an altered 

 porphyrite. Both the first and second of these have been 

 fully described by Dr. F. D. Adams.^ Of the former, Dr. 

 Adams says, " the alteration to serpentine was found to 

 be complete, with the exception of a few irregular-shaped 

 remnants which occur in one of them. . . . They are 

 probably bastite or some allied mineral derived from the 

 alteration of a rhombic pyroxene, which was a constituent 

 of the rock from which the serpentine was derived." 



The hornblende granite is described as " composed essen- 

 tially of quartz, orthoclase, plagioclase and hornblende, with 

 a little titanic iron ore. The hornblende, as is usual in gran- 

 ites, seldom has a good crystalline form. It is light green in 

 color, strongly pleochroic, shows in many places the char- 

 acteristic cleavage and often occurs twinned. It sometimes 

 contains little pleochroic ' hofe ' surrounding minute 

 doubly refracting crystals. Its angle of extinction, as is 

 often the case with the hornblende in granites, is large. 

 The greatest angle measured was 24°, and this was in a 

 section in the zone of the orthopiiuieoid and clinopinacoid, 

 nearly but not quite coinciding with the latter plane. 

 Many of these hornblende grains assume a fibrous form at 

 their edge, but this is especially the case at the extrend- 



1 "Notes oil the Microscopic Stiucture of some Rocks of tlie Quebec Group," by 

 F. D. Adams. R"p. Geol. Sui-v. Can., 1S80-1-2, i>art A. 



