[ells] notes on rock-contacts IN KINGSTON DISTRICT 105 



tions between the Potsdam formation and the Black Kiver limestone 

 formation. This is further accentuated by the fact that differences 

 of elevation do not apparently affect the peculiar conditions of deposi- 

 tion over large areas. 



An illustration of this peculiarity of deposition is seen in the 

 sandstone area in which Gildersleeve's quarry is located. Thus, at 

 the quarry itself the sandstone has a thickness of not far from 60 to 

 70 feet, but at the eastern side of the basin, about two miles distant, 

 the exposed thickness is only a few inches, and at Kingston mills, a 

 few miles further east, at the same level there is no trace of the sand- 

 stone at all. There is no sign of faulting anywhere in these rocks. 



Owing to the apparent stratigraphical conformity between the 

 lowest sandstones and the overlying formations there is no visible reason 

 why the Calciferous dolomites should not succeed the Potsdam sand- 

 stone on the south as well as in their regular order on the north of the 

 axis. Murray, in 1853, records the presence of calcareous sandstone 

 further west, in a section on the Crow river near the Marmora iron 

 works, with light brownish gray limestone and greenish shales which 

 underlie the lithographic beds of the district, the lowest portion of 

 which he regarded as possibly of Calciferous age, with a thickness of 

 about twenty feet, while the next twenty feet of the section might be 

 possibly regarded as of Chazy age, the upper portion being characterized 

 by the peculiar large fossils of the Black Kiver formation as in the 

 southern part of Kingston city. It is possible, however, that 

 with the exception of six to eight feet of the basal beds which 

 rest upon the gneiss and which may probably represent the 

 Potsdam, the rest of the section is the equivalent of that seen on 

 Howe island in the St. Lawrence or the lower beds of Barrie- 

 field hill and Kingston Mills. Unless it is possible to correlate the 

 lower 100 feet of this limestone series with the Chazy of the Ottawa 

 basin it is necessary to extend the Black Eiver formation downward 

 to a very much greater thickness than is found anywhere else in eastern 

 Ontario, since the true Black Kiver strata with the characteristic fos- 

 sils of the Ottawa river basin occupy only the upper portion of the 

 formation. In this case we must conclude that the fossils of the 

 lower part, which are few in number comparatively speaking, must 

 pertain to the upper Chazy, notwithstanding their apparent resemblance 

 to some forms found in the Black Kiver limestones elsewhere. That is 

 certain forms must be common to the two formations of the Chazy and 

 Black River limestones. Even then we have no trace of the lower por- 

 tion of the Chazy represented in the Ottawa basin by about 100 feet of 



Sec. IV, 1903. 6. 



