65 



a general course of S.W. to N.E. and a sleep hade, and where the dip 

 of the bed is at an angle with the course, or the beds are flat, the 

 fossils they contain are more or less distorted and often are quite un- 

 recognizable. 



There are two areas, however, which have not been so much affected 

 by this cause of effacement of fossils, namely the valleys of McLeod 

 and Indian brooks. A third, the Mira valley, also has fossils in good 

 condition, especially when preserved in limestone layers. 



Although there is considerable lime diffused as a cement through 

 the Cambrian terranes, heavy masses of limestone are unknown in 

 them. But a few thin limestone beds are found in the upper division 

 (Bretonian) of the St. John terrane. This is in contrast with the 

 rocks of the pre-Cambrian complex, which possesses large bodies of 

 gray limestone, and with the overlying Lower Carboniferous terrane, 

 in which also considerable limestone masses and gypsum beds are 

 found. 



Some difference in condition may be noted between the s'ates of the Slates of the 

 Etcheminian and those of the Coldbrook terrane. The latter have terrane dis- 

 suffered more from sliding movements so that the fossils in these slates thaiTtho 1018 

 have been much obscured ; it is only where they have been imbedded of the 

 in phosphatic nodules that the form 5 of the fossils have been preserved. 

 But this ca,n hardly be regarded as a proof that the terrane in which 

 they are badly preserved has been subjected to greater rnetainorphism 

 than the one in which the fossils are in better condition, for in the Cold- 

 brook terrane these fossils are contained in a bed of slates only thirty 

 feet thick, while the rest of the terrane consists of conglomerates, 

 agglomerates and other trap- rocks, which would have resisted dynamical 

 movements more energetically, and the slates would have suffered 

 proportionately the more. 



The small amount of alteration which has affected the Cambrian Cambrian of 

 strata in Cape Breton, would indicate that they have never been very deeply buried, 

 deeply buried. The whole thickness of the three terranes was not 

 sufficient to bring the lower beds within the influence of the heat 

 of the earth's interior ; and they could not at any time since their 

 formation have been deeply buried beneath more recent terranes. 

 And even the Lower Carboniferous may not have covered them every- 

 where, for Mr. Fletcher in several places represents the Cambrian as 

 covered directly by the millstone grit. 



The action of pressure from the direction of the Atlantic ocean is 

 everywhere traceable in the Cambrian terranes, and quite corresponds 



5 c. H. 



