[ei-ls] notes on rock-contacts IN KINGSTON DISTRICT 107 



whicli prevailed north of that axis throughout the Ottawa basin; and 

 it may be supposed that, at a certain stage in the deposition of the 

 sandstone formation, the surface was raised above the level of the 

 sea and so remained till the beginning of the Black River time through- 

 out the whole extent of Lake Ontario. Then by gradual subsidence 

 the conditions for the deposition of the Black River and Trenton lime- 

 stones were again resumed, at first in shallow w^ater, producing shales 

 and fine conglomerates until the submergence gradually became greater, 

 60 that marine limestones were laid down, and the succession of for- 

 mations upward thence continued in regular order. The reasons for 

 these apparently somewhat sudden and, in places, local changes of 

 level at the period of deposition of these old sediments have not yet 

 been satisfactorily explained. 



Such peculiarities of deposition are not, however, confined to the 

 part of the St. Lawrence basin under consideration. Similar unequal 

 phases of elevation and subsidence are readily recognized in the Ottawa 

 basin; in that part of the province of Quebec north of the St. Lawrence 

 river below Montreal; and in New Brunswick and Nova Scotia. 



Thus, on Lake Nipissing at the head of the Ottawa river basin on 

 the west, the lowest sediments, resting on the crystalline rocks, have 

 been found to contain fossils of Black River age, while in the same basin 

 at the northern end of Lake Temiskaming, the basal beds belong to the 

 horizon of the Niagara formation or are a part of the Upper Silurian 

 series. Along the lower St. Lawrence below Montreal, the Potsdam, 

 Calciferous, Chazy and the succeeding formations are regularly developed 

 as far east as the St. Maurice river ; but, below this, the Laurentian rocks 

 are overlapped successively by the Calciferous and new^er formations 

 until at the Montmorency Falls below Quebec the basal beds upon the 

 gneiss are of Trenton age. This irregularity in deposition is not due to 

 the agency of faults on the north side of the St. Lawrence, though great 

 displacements of strata are due to this cause in the country to the south. 



In New Brunswick there are many gaps at different points. Some 

 of these apparent unconformities are due to faults, but in the eastern 

 area along the Gulf of St. Lawrence, the rocks of the great Carbonifer- 

 ous basin which consist for the most part of conglomerates, sandstones 

 and shales of the Millstone grit division, are directly overlaid by soft red 

 beds of upper Carboniferous, or, as they are sometimes styled, of 

 Permian age. In this case the great thickness of strata belonging to the 

 productive coal formation which are so well developed in the Spring- 

 hill, Pictou and Sydney basins of Nova Scotia, are practically absent 

 and have apparently never been deposited. Similar overlaps of the 

 upper formation upon Millstone grit or lower Carboniferous are seen 

 iu the last named province along the south side of Northumberland 



