DIVERSE FORMATIONS OP SOUTHEASTERN QUEBEC. 459 



the province of Quebec. In this map many changes in the geology of this 

 area, as compared with the formations indicated on the general map of 

 Canada, 1866, are apparent. It was found that much of what was then 

 regarded as of Upper Silurian age, comprising the great stretch of country 

 lying to the east of the Sherbrooke and Lennoxville belt of crystalline schists 

 and forming the extension northward of the rocks described some years 

 before by Professor Hitchcock as the Calciferous mica schists and Coos 

 groups, really belonged, in great part, to an older system. This fact was 

 established not only by its unconformable position beneath fossiliferous 

 Silurian rocks, but by the finding at several points of Cambro-Silurian fossils, 

 both in the limestones of the series and in certain interstratified beds of 

 black graphitic slates. The fossils comprised graptolites of Trenton-Utica 

 age, as determined by Professor Charles Lapworth, similar in character to 

 those obtained from the graphitic shales of the south side of the St. Law- 

 rence — recent examinations having disclosed the presence of these in large 

 quantities and in an excellent state of preservation — together with criuoids 

 and other forms, which under the microscope were found to indicate a hori- 

 zon of the lower Trenton or possibly upper Chazy. The Upper Silurian 

 areas were limited to basins of small extent or closely infolded beds, and 

 were in all cases clearly distinguishable by their characteristic fossils. 



The underlying rocks were divisible into at least two portions, of which 

 the lower or crystalline series, composed of schists of various kinds with epi- 

 dotic, chloritic, and dioritic rocks, occurred as well-defined anticliuals. Of 

 these, in the section from Richmond to Maine, three principal axes were 

 recognized. The first axis, or that near Richmond, was traced and found to 

 be the extension of the Sutton mountain anticlinal, formerly recognized by 

 Dr. Selwyn ; the second or middle axis passed through Sherbrooke ; and the 

 third constituted the belt of high land along the border of New Hampshire 

 and Maine, the character and probable age of which had been indicated by 

 Professor Hitchcock some years before. In all these the rocks present 

 great similarity in lithological aspect, and are frequently flanked by slates 

 and conglomerates with interstratified beds of hard quartzite or quartzose 

 sandstone, in places having a somewhat schistose structure. In these areas 

 of crystalline rocks the principal deposits of metallic ores are found, and 

 they are now regarded as of pre-Cambrian and probably Huronian age. 



The series intermediate between that just described and the rocks of the 

 great Cambro-Silurian eastern and central basins comprises slates, mostly 

 blackish and often wrinkled, but also of green and purple shades and with 

 interstratified beds of hard grayish sandstone which sometimes becomes a 

 bluish-gray quartzite. In places these rocks are unconformable to the un- 

 derlying schists, and contain masses of conglomerate often of considerable 



