Pctrographical Relations of Laiirentian Limestones. 7 



doubtless, by the heat from the mass below, and under the 

 burden of the rocks above, x have, instead, flowed, so that 

 they accommodated themselves to the rather irregular 

 form of the invading mass, and now, everywhere, their 

 strike is seen to be the result of this intrusion and parallel 

 to its boundary. 



This subject of the flow of marble and limestone has 

 been most carefully and convincingly dealt with experi- 

 mentally by Dr. Adams. 2 Some of the structures so 

 produced artificially in Carara marble have been compared 

 by him with structures exhibited by the limestones of 

 this very district and found to be identical. 3 



It is not alone to the limestones, however, that this 

 peculiarity of strike belongs. The foliation of the amphi- 

 bolites and gneisses forming the contact zone correspond 

 to the strike of the limestone and the form of the intrusion ; 

 while even the rocks of this mass itself are foliated and 

 banded, and both foliation and banding are parallel to its 

 boundary. Cases which appear entirely analogous to this, 

 as regards the matter of uniformity of strike and foliation, 

 have been observed in the Eainy Lake region 4 and in the 

 district about the Lake of the Woods, 5 where the so-called 

 Fundamental Gneiss penetrates the Huronian. 



In their endeavours to trace back as far as possible the 

 geological history of the earth as recorded by the stratified 

 deposits in its crust, the early workers — possibly deceived 

 by the outward resemblance of these intrusive rocks to 

 undoubted clastic rocks present in later geological forma- 

 tions, which were known to have undergone extensive 



1. Heim, A., " Geologie der Hochalpen zwiclien Reuss unci Rhein," Beitrage zur 

 Geol. Karte der Scliweiz, Vol. XXV., Bern, 1891. 



1 2. Adams, P. D.. and Nicolson, J. T., "An Experimental Investigation into the 

 Plow of Marble," Phil. Trans. Roy. Soc. London, 1901, Series A, Vol. 195, pp. 3(53-401. 

 See also Van Hise, C. R., " Metamorphism of Rocks and Rock Flovvage," Bull. Geol. 

 Soc. Am., 1898, Vol. IX., pp. 295-313, 318-326. 



3. Loe. cit,, pp. 389-390. 



4. Lawson, A. C, Geol. Surv. Can., Ann. Rep't., 1888, Vol. III., Part P. 



5. Ibid., 1885, Vol. I., Part CC. 



