74 J. A. Dresser —Study in the Metamorpliic Rocks 



the south in the opposite direction, or about southeast. The 

 limestone would thus form the axis of the anticline. This 

 view was held by Logan, while Ells takes the ground that the 

 limestone is of much more recent formation than the other 

 rocks of the section and has been infolded into its present posi- 

 tion, but just in what manner has not been explained, other- 

 wise than as by " an intricate system of folding and faults." 

 The former placed all these rocks in the Quebec Group, of 

 Calciferous-Chazy age, while the latter regards the limestone as 

 Lower Trenton and all the other rocks as Precambrian. 



While Logan believed all the rocks of this section to be of 

 sedimentary origin, and also included the serpentine belt at 

 the south in the same class, correlating it with the dolomite on 

 the ground of the magnesian character of each, Selwyn and Ells 

 recognized the igneous origin of the serpentine, but still 

 included the twelve thousand feet, or more, of trap in the 



3 



9 ftti 4 3 i 





northern part of the section with the clastic rocks. Hence 

 the results of both investigations may be reasonably submitted 

 for reconsideration. 



There appears to the writer no reason to believe that there 

 was any great time-break in the deposition of the sedimentary 

 rocks of this section. The contacts are transitional and the 

 black limestone has suffered from dynamic metamorphism no 

 less than the mica schists. 



It is, moreover, an apparent fact that the dolomitic schist can- 

 not be referred to the Precambrian from the presence of the 

 fossils already referred to in the non-magnesian limestone masses 

 included in the dolomite. The importance of this isolated 

 occurrence of fossils in the dolomite seems to have been lost 

 sight of in the more recent work of the Geological Survey, by 

 the exposure having been erroneously connected with the 

 black limestone three-quarters of a mile distant. For in the 

 Sherbrooke and Montreal sheets of the Eastern Townships 

 map of the Geological Survey of Canada (1886-1894), the local- 

 ity of these fossils, Lot 11, Range xii of the township of Cleve- 

 land, is included in the Trenton area by a peculiar indentation, 

 D-D fig. 4, in the part colored Precambrian, the boundaries 

 of which are thus made to cross the actual stratification of the 

 * Fossils at this point. 



