BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 VOL. 17, PP. 497-522, PLS. 67~68 OCTOBER 18, 1906 



IGNEOUS ROCKS OF THE EASTERN TOWNSHIPS OF QUEBEC 



BY JOHN A. DRESSER 



(Read before the Society December 27, 1905) 



CONTENTS. 



Page 



Area defined 497 



Geography of the region 498 



General geology 498 



Previous geological research 499 



The pre-Cambrian copper-bearing volcanics 501 



Possible pre-Cainbrian sediments 505 



The serpentines and diabases 509 



The granites 514 



The later dikes 515 



The Monteregian hills 517 



Chemical analyses of type rocks from the Monteregian hills 519 



Genetic relations of the igneous rocks 519 



Summary 522 



Addendum 522 



Area defined 



That portion of the province of Quebec which has been affected by the 

 Appalachian uplift lies wholly to the south of the Saint Lawrence river. 

 It comprises two somewhat distinct parts, the mountainous region of the 

 Gaspe peninsula along the lower Saint Lawrence and the hilly country 

 from the Chaudiere river to the international boundary line between the 

 province of Quebec and the states of Maine, New Hampshire, and Ver- 

 mont. The interval between the two portions is marked only by a sub- 

 sidence in the Appalachian hills southeast of the city of Quebec. 



The second of these two areas is commonly designated as the "Eastern 

 townships." Being less easily accessible, on account of its hilly character 

 as well as its position, and also less desirable otherwise for settlement, 

 this region was not surveyed until some thirty years after the cession 

 of Canada to England. It was then divided into townships approx- 

 XLV — Bull. Ghol. Soc. Am., Vol. 17, 1905 (497) 



