28 



BULLETIN OF THE 



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prove the presence of tbe same one in another, except by direct connec- 

 tion, even if the two do look alike, especially if that sameness is ques- 

 tioned. If the two rocks are identical in structure and composition, 

 nothing but the proof of direct, absolute continuity places the question 

 of thei^'r identity beyond dispute here, especially if we have any reason 

 to suspect the eruptive origin of one or both of them. Lamination, 

 banding, joint planes, cleavage, pseudo-stratification, and fluidal struc- 

 ture, are not to be taken as proof of stratification in doubtful rocks. 

 The' very origin and nature of all, except, perhaps, the true lluidal 

 (not pseudo^fluidal) structure, arc yet open questions. Until it is 

 proved that they are confined to one class of rocks, it is unsafe to use 

 them to prove that any questionable rock belongs to that class. Doubly 

 so is it when it is well known that they are not so confined. If they 

 are not to be used to determine the sedimentary origin of a rock, in like 

 manner the dip and strike of such structures ought not to be taken to 

 prove order of superposition, conformability, or non-conformability, 

 especially as this proceeds upon the supposition that both rocks in 

 question are sedimentary. That a sedimentary rock is horizontal, or 

 has a certain dip at one place, is not to be taken as proof of what its 

 position must be in another locality, unless the conditions remain the 



same. 



It may be said that every rock carries in itself, or in its relations to 



its associates, or both, its history, more or l^'ss complete. In order 

 to read and understand this history, it seems necessary that we should 

 be able to distinguish between the fragmcntal and non^fragmcntal 

 forms • the characters assumed by a lava flow and its associated 

 detritus, their relations to one another and to the over and underlying 

 rocks; the characters of an intrusive rock, its effect upon the country 

 rock, and the nature and kind of junction that they make with each 

 other ; tlic relations that sedimentary rocks have to their over- and 

 nnder-lying rocks ; and the alterations to which all classes are subjected. 

 One of thc^iost common errors made, is by observers taking the ground 

 ■ that two outcropphig rocks that look alike are of necessity the same 

 geologically, and form a continuous whole, although no direct connection 



is proved. 



It now remains for us to enter upon the questions before us. 



The Jasper and Iron Ore. 



The country rock is of a varying nature, but is mainly composed of 

 schists (largely chloritic), argillitcs, and quartzite, in that part of the 



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