106 ROYAL SOCIETY OF CANADA 



greenish and sometimes red coloured shales, or of the dolomites of Calci- 

 ferous age. 



From a consideration of the facts regarding the deposition of the 

 several formations of Palasozoic age in this district, it would seem that 

 in this portion of the province of Ontario as also in a part of the state 

 of New York adjacent on the east, the regular sequence of these forma- 

 tions has been affected by causes not directly observable at the present 

 time, by which certain members of the geological scale have been omitted. 

 Such gaps have not been caused by faulting, but are due rather to local 

 differences in elevation which have affected certain portions of the area 

 in question, since practically on the same present general level, and with- 

 in a comparatively limited space, we find different formations ranging 

 from the Potsdam to the Black Eiver, constituting the lowest beds which 

 rest upon the Archœan floor. Otherwise, if we regard the several forma- 

 tions from the Potsdam upward as having been deposited with equal 

 regularity, it would appear that prior to the deposition of the lower por- 

 tion of the Black Eiver formation, both the Calciferous and Chazy with, 

 in many places, all the Potsdam have been removed by denudation before 

 the Black Eiver limestone was deposited. In this case it is remarkable 

 that all the similar formations on the north side of the Archœan axis, a 

 short distance to the north, should have escaped such denudation, 

 especially in view of the fact that the whole country northward from the 

 vicinity of Kingston to the Ottawa is comparatively level and not now 

 affected by marked elevation in any part. 



From an examination of the logs of several deep borings, made in 

 the townships of Bertie and Willoughby in the Niagara peninsula, it 

 would appear that similar gaps in the geological scale to those which 

 occur in the Kingston district are a feature of the district. In two of 

 these borings which were sunk to a depth of over 3,000 feet in the search 

 for natural gas, the succession of formations downward is regular from 

 the Onondaga to the Trenton, but the next underlying formation was 

 found to be a yellowish sandstone, regarded by the drillers as of Calci- 

 ferous age, but whicli may represent some portion of the Potsdam sand- 

 stone, since throughout the eastern area the true Calciferous consists for 

 the most part of dolomitic limestone. In this case the Black Eiver, the 

 Chazy and the Calciferous dolomite are all absent, so that the conditions 

 of deposition in that district are similar to those already described as 

 occurring at and near Kingston. 



It would, therefore, appear tliat some marked but well defined 

 change of level occurred in the area south of the Kingston-Brockville 

 Archaean axis at the close of the Potsdam, which was also materially 

 reduced in thickness. This is in marked contrast to the conditions 



