32 Canadian Record of Science. 
still finer grained black material, the latter standing out on 
weathered surfaces. Both these constituents, however, 
were found to be carbonates, differing only in the relative 
freedom of their effervescence with acids. Included in 
these calcareous portions there will also be seen at places 
nodules and inclusions of chert standing out on weathered 
surfaces and presenting hackly exterior surfaces. Onespe- 
cimen collected shewed, in a calcareous base, angular frag- 
ments of black chert, which had apparently been portions 
of continuous cherty layers, some cause having subse- 
quently etfected their fracture. 
Before leaving the consideration of the macroscopic 
character of these rocks it should be stated that, whilst the 
variation of their characteristics is endless, the ditferent 
varieties are not confined to any definite horizon in the 
subdivision to which they belong, and in a short distance 
in the same bed what will at one place be a typical flinty 
chert may be found to become granular or, by increasing 
preponderance of the earthy carbonates, to merge into a cal- 
careous or dolomitic rock. Neither is the demarcation be- 
tween the upper and lower divisions of the formation sharp, 
the delimitation being based upon the great preponderance 
of the argillaceous members in the former as contrasted 
with the essentially siliceous constitution of the latter. In 
fact, very siliceous or dolomitic portions are often found 
in the argillites, whilst beds of dark argillite and shale 
have been found amongst the lower cherty series. 
Here then we have a number of rocks very dissimilar in 
nature, yet apparently forming interchangeable members 
of the series and at places merging one into the other. 
That they are much altered from their original condition is 
- evident, and that they still occupy their original position as 
deposited, precludes the idea of .any dynamic meta- 
morphism nor do they show any signs of such action in 
other respects. The argillites show nothing but ordinary 
rock jointing apart from the bedding planes, no trace of 
slaty cleavage being present. 
Their present condition would seom to be due to a quietly 
