126 THE PE>OKEE IRON-BEARING SERIES. 



order to prove that such a trausforuiatiou has occurred, it is necessary to 

 show that the rock in which they have been found to occur was a frag- 

 mental one. Tlie rounded cores in a quartzite are sufficient to show this, 

 but in the case of a recrystalhzation of fehlspar it is necessary actually to 

 trace the crystalline rock back to its fragniental state. The moditied frag- 

 mental rocks of these kinds in the Penokee series reveal themselves as 

 such with little difficulty. Upon succeeding pages it is remarked that 

 whenever quartz is present in them as a fragmental constituent, even if 

 associated with ([uartz not of this origin, it is easily discovei'ed. Its original 

 outlines are so strongly marked by particles of gas, iron oxide, and other 

 inclusions that all subsequent changes seem inadequate to obliterate them. 

 While this is the case with these known fragmental rocks, the complete 

 absence of anything which suggests that there have been cores in any case 

 in the sections of the crystalline schists loses largely its force as negative 

 evidence against a fragmental origin; Jaecause the fragmental rocks inen- 

 tioned are nowhere foliated, while the schists'are strongly foliated. Frag- 

 mental rocks in other districts which have been subject to dynamic forces, 

 and have therefore become foliated, have rapidly lost evidence of their 

 original fragmental character. 



To conclude, if the massive, coarsely crystalline rocks are assumed to 

 be of eruptive origin, it necessarily follows that a large number of the 

 schistose ones are certainly derived from them; also, it has not been possi- 

 ble to trace any of tliese crystalline schists back to a fragmental rock. 



