64 BAILF.Y ON GEOLOGY OF 



certainty either their order of succession, their thickness, or their exact horizon. In 

 attempting to solve these questions it occurred to the author that some valuable 

 information might be gained by instituting comparisons between the succession of beds 

 upon the extreme southern and the extreme northern edge of the general Silurian basin, 

 the one being found on the Beccaguimio River, in Carleton County, and the other on Lake 

 Temiscouata, in the Province of Quebec. With a view at the same time to the more ready 

 recognition of any Devonian strata which the region might contain, examinations were 

 made in portions of northern Maine, more particularly in the region of the Fish River 

 Lakes and that of Aroostook River, in both of which such Devonian strata had been 

 represented as occurring. These comj)arisons proved unexpectedly interesting by show- 

 ing not only that large tracts of what had, in the maps of Maine, been represented as 

 Devonian were in reality Silurian, but that, both in the character and succession of the 

 beds, as well as in the associated fossils, these three widely-separated localities exhibited 

 such a close parallelism as to leave little doubt of their essential synchronism. Some of 

 the facts bearing upon these comparisons have already been given in the Transactions of 

 the Society, but more recently much further information relating to the same subject has 

 been obtained, so that we are now in a position not only to correlate, with some degree 

 of certainty, the several divisions of the Silurian system as seen through the extensive 

 tract extending from Cape Gaspé to northern Maine, but also to compare the nature and 

 origin of these several subdiA^isious with those of the same formation in southern New 

 Brunswick. 



Of the three localities to which reference has been made, the most interesting and 

 instructive is that of Lake Temiscouata, and may well serve as a basis of comparison for 

 the entire region of which it forms a part. As indicated in the sections given in the 

 " Geology of Canada," the strata here exposed fall naturally into three great groups, the 

 first consisting essentially of limestones, more or less pure, and abounding in fossils, but 

 having at their base a considerable thickness of grey and white sandstones, with some 

 conglomerate ; the second consisting largely of sandy shales, but having beneath them 

 over 1,000 feet of coarse conglomerate (Burnt Point conglomerates), and at their summit 

 heavy beds of coarse somewhat epidotic sandstones (Point aux Trembles sandstones), and 

 thirdly, an apparently great thickness of very fine slates and sandstones, the latter 

 occupying all the lower half of the lake, and spreading widely over northern New 

 Brunswick. The attitude of these groups is as strongly contrasted as is their character, 

 the rocks of the first or Mount "Wissick division having but a low inclination (varying 

 from 13° to 30°), while those of the second have a much steeper, but at the same time very 

 regular dip of about 60° to the southward, while those of the third, exhibit only a sys<em 

 of abrupt and complicated foldings. Actual contacts between the several diAdsions are 

 not visible ; but from the circumstance that in all three the general dip is to the south, 

 and further that the rocks at the base of Mount Wissick rest directly and unconformably 

 upon beds of the Quebec group, it was, in the author's first paper upon the subject 

 (Trans. Roy. Soc. Can., Vol. IV) suggested that these were probably the lowest beds, 

 and that those of the second and third divisions followed the order of their apparent 

 succession. It was, however, at the same time stated that until a more complete 

 examination had been made of the fossils collected, not only from Mount "Wissick, but from 

 Point aux Trembles, no definite conclusions upon this point could be reached. Since 



