49 



But though there are no clear sections of this division in the Mira 

 valley that have come under our observation, except at McLean 

 brook, there is ample evidence that it is well developed there. In the 

 centre of the valley is an important settlement known as ' Big Ridge,' 

 which is spread along the principal ridge of Johannian rocks in this 

 valley. It lies between McNeil brook and Trout brook, and extends 

 to the old French road. On each side of this main ridge are two Ridges at Mc- 

 other lower swells of the same rocks, one filling in the space between 

 McNeil brook and the Mira river (except the narrow belt of Bretonian 

 shales extending along the course of McNeil brook), the other lying 

 in the valley of Trout brook. The rocks of these several ridges meet 

 along the Mira river, which is bordered by Johannian flags and s^tes 

 from Marion bridge well down toward Albert bridge. 



The Bretonian Division. 



In the Barachois valley, at the railroad cutting on the east side of 

 the Barachois pond, a considerable thickness of fine, dark, soft clay 

 slates is exposed. These are the first measures going south and east Bretonian 

 of the Bras d'Or met with in Cape Breton, that can with certainty be Baradiois 

 assigned to the Bretonian division of the St. John group. At the roac '- 

 east end of the cutting they dip S. 40 W. mag. < 5; about the 

 middle of the cutting their dip is S. 30 W. mag. < 10. Here there 

 is a small syncline, and at the further end of the cutting the dip is 

 increased to S. 30 E. mag. < 50. Although there are some rows of 

 small calcareous lentiles in these beds, by which the dip was deter- 

 mined, no fossils were found in them. 



McLeod brook enters the upper end of Barachois pond. Following 

 up this brook, no other part of the St. J ohn terrane is met with besides 

 these soft dark slates. The valley along here is bordered by syenites 

 on the south-east and by effusive rocks on the north-west. But near 

 the head of the valley the Etcheminian sandstones previously referred 

 to form a narrow border for a short distance on the north-west side. 

 In ascending McLeod brook from the Barachois pond the dip of the Bretonian 

 Bretonian slates, where it has been observed, for a distance of two and 



a half miles up stream, is low 10 to 30 degrees ; then the beds stand 

 at higher angles and mostly dip toward the south-east side of the valley ; 

 but in other parts they also dip south-west and north-west. At 

 Johnson's little brook, which comes down over a cliff of syenite, there 

 is a thin bed of limestone containing shells of Orthis lenticularis and 

 a Camarella (?) ; this limestone is contained in black carbonaceous 

 shale. Mr. Fletcher found Dictyonema flabelliformis here. 

 4 c. R. 



