Geology and Mineralogy. 315 
chrysotile and veins of baryta and galena. 
You will t i 
tion; while the great body of apatite-bearing rock is at the very 
mmit ” 
Having established this important sequence my thoughts at 
once flew back to the discoveries of phosphatic nodules and shells 
in the Lower Silurian rocks at the Allumettes Rapids (Geology of 
Canada, page 125), and in several places in the eastern townships 
and elsewhere. Is it not probable that the source of our mineral 
apatite is in the Lower Silurian rocks, whence it has enetrated 
into the upper portion of the second division of the Laurentian 
system? Or, may the Hozoon not have furnished a considerable 
long with the Eozoon, but if so their remains have been entirely 
obliterated by crystallization or other metamorphism. in 
that the gap between the Lo Silurian and uppermost crystal- 
eral of my bands of limestone, and I fail entirely to discover Sir 
William’s upper distinct system—yet I have been over the same 
ground, 
The Huronian and Hastings series of rocks I believe to be sim- 
ply an altered condition, on their westward extension, of the 
ower portion of my second system ; and this alteration com- 
mences as this portion reaches Hastings county, where you will 
