204 Canadian Record of Science. 



thirty-five miles in length, in the heart of the Appa- 

 lachian uplift and following the strike of the Appalachian 

 folding. Many of them, as Owl's Head and Orford moun- 

 tain, rise to a very considerable height, these peaks hav- 

 ing a height of about 2,400 and 2,800 feet respectively ; 

 forming, in fact, the highest elevation in this part of Can- 

 ada. So far as has been ascertained, these mountains are 

 in all cases composed of highly altered rocks. Many of 

 them are altered diabases. 1 In other cases the alteration 

 is so far advanced that it is impossible to determine the 

 character of the original rock. Many of them have been 

 completely altered to masses of serpentine. Nepheline- 

 syenites, essexites, and similar rocks have not as yet been 

 found anywhere in this chain of hills. A series of dyke 

 rocks from Lake Memphremagog, examined by Marsters, a 

 were found to be chiefly granites and lamprophyres, with 

 one typical camptonite. It would seem therefore, that 

 while our knowledge of these hills is as yet very imperfect, 

 the evidence at our command, so far as it goes, points to 

 them as belonging to a group quite distinct from Mount 

 Eoyal and its associates. The petrographical province of 

 the Monteregian hills may, therefore, in the present state 

 of our knowledge, be said to comprise only the eight 

 mountains enumerated on p. 240, together with the con- 

 sanguineous dykes which at many points are found cutting 

 the rocks of the surrounding plains. 



The first description of these hills was that given by 

 Logan and Hunt in the early years of the Canadian Sur- 

 vey. To Hunt especially we owe a somewhat extended 

 description of the petrography of the group and a number 

 of chemical analyses, more especially of the constituent 

 minerals of certain of the rocks. These descriptions are, 

 however, very general and often very imperfect, as must 

 necessarily have been the case before the introduction of 

 modern petrographical methods. Nor were certain im- 



1 F. D. Adams, Ann. Rept. Geol. Surv. of Canada, 1880-81-8J, pp. 12-13 A. 



2 American Geologist, July, 1895, 



