No. 6.] MISCELLANEOUS — ARCH^AN OP CANADA. 375 



highest band of crystalline limestone yet found, although this 

 fossil may, and indeed has been sparingly found in some of the 

 lower limestones. The celebrated Petite Nation locality for 

 Eozoon, has now heen proved to be on this highest band of lime- 

 stone, and in fact in the most recent portion of my second system; 

 the zone of limestone in which this fossil occurs is especially 

 characterized by an abundance of serpentine and chrysotile. It 

 is further traversed by veins filled with baryta and galena, and 

 these also extend up through the Potsdam and Calciferous 

 formations, but do not enter far into the crystalline rocks, both 

 minerals rapidly giving out as we descend into these older rocks; 

 while the fissures themselves narrow to threads and bifurcate. 

 This fact has been proved by a close and careful investigation 

 in Rossie, N. Y., and Landsuowne, Loughborough, Bedford, 

 Madoc, and Tudor, in Canada. 



Immediately beneath the Eozoon limestone the apatite-bearing 

 belt of rocks comes in with horizons of both hematitic and mag- 

 netic iron ores — chiefly the former ; and immediately below these 

 again a great belt of plumbago bearing rock (extensively wrought 

 for this mineral in Buckingham and Lochaber, Ottawa county), 

 an important volume of crystalline limestone filled with rust- 

 colored lumps and beds. This band of limestone is the second in 

 descending order. A short distance beneath this last (some 

 twenty or thirty chains), is an important and well-marked horizon 

 of magnetic iron ore — occasionally with layers of hematite, in 

 which occur a number of promising mines (e. g. the Baldwin and 

 Forsythe mines, Hull, P. Q. ; the Christies' Lake and Silver Lake 

 mines in South Sherbrooke, Lanark county, Ontario, etc.) 



On a still lower horizon and close to the third belt of limestone, 

 there is another iron ore horizon of coarsely crystalline magnetite 

 with apatite intimately associated,. which has now been identified 

 and followed continuously for upwards of one hundred miles. 



Lastly, in a still lower, fourth and last important volume of 

 limestone, we find some large deposits of hematite iron ore (e. g. 

 the Cowan mine in Dalhousie township, Lanark county), but 

 these, in so far as investigated, are superficial deposits, only pene- 

 trating some fifty or eighty feet into the limestone ; but the par- 

 ticular layer in which they occur may be followed by its deep 

 hematite red color throughout a great extent of country. 



The order then thus given to the economic minerals, just men- 

 tioned, is, in ascending order, as follows : — 1st, hematitic iron ore; 



