GEOLOGICAL AREAS OF CANADA. 99 



their exact age somewhat doubtful ; but they appear to consist of 

 representatives of Lower and Upper Silurian, Devonian, and Lower 

 CarboniferouSj formations. 



The Potsdam formation has been recognized at points on the St. 

 Lawrence, between the Chaudik'e and the Trois Pistoles, in Temis- 

 couata ; and a sti-ip of the Hudson River formation, represented by 

 a series of contorted sandstones, dolomites, and bituminous shales, 

 occurs along the coast of Gaspe, between the River M rsouin and Anse 

 a la Tierce. The more important strata of the district, however, com- 

 prise representatives of the Quebec group (see below), with the over- 

 lying Gasp6 limestones and sandstones (Upper Silurian and Devonian 

 formations), and the Lower Carboniferous Bonaventu re-formation of 

 South Gaspe. The Quebec group of strata occupies, apparently, a 

 position between the Calciferous and Chazy formations of other 

 localities, or otherwise represents the two series combined. It is 

 subdivided into three formations — comprising in ascending order : — 

 (i.) The Levis formation, made up principally of black graptolitic 

 shales or slates, containing numerous graptolites and other fossils ; 

 (ii.) the Lauzun formation, consisting in pai't of red and green shales, 

 sandstones, and dolomites, but composed mostly of metamorphic strata, 

 among which talcose and other magnesian rocks (chloritic schists, 

 serpentines, &c.) largely predominate — the lower and upper portions 

 of the series containing many bands of copper ore and other metalli- 

 ferous deposits; and (iii.), the Sillery formation, consisting chiefly of 

 red and green shales, sandstones, and dolomites, but including, in 

 places, altered rocks in the form of crystalline schists and epidotic 

 and gneissoid strata. The Levis formation occurs prominently around 

 the City of Quebec and Point Levis, chiefly in the form of hard black 

 shales dipping at high angles ; but it is also seen around Richmond, 

 on the St. Francis, and in the neiglibouring townships, as well as 

 around Phillipsburg, on the boundary line, and, again, east of the 

 Chaudi^re. It is of much palteontological interest from the gi'eat 

 number of graptolites obtained from its strata. The altered and 

 metalliferous Lauzun division occurs more or less throughout the 

 Eastern Townships, or between the north-east shore of Lake Cham- 

 plain and the Chaudiere River, generally. It is especially rich in 

 copper ores ; but contains, also, chromic iron ore, magnetic iron ore, 

 specular iron schists, gold in quartz bands and veins, galena, serpen 

 tines and serpentine-mai-bles, roofing slates, and other economic sub- 



