56 Canadian Record of Science. 



from Archaean to early Devonian. They are embedded in 

 an extremely fine grained greyish matrix, which weathers 

 to a rusty brown. The rocks represented are red and black 

 shales, hornstone, limestone, mainly Trenton, red and grey 

 sandstones, the latter probably Potsdam, quartzite, granite 

 and syenite gneiss. 



No trace of stratification could be seen but vertical 

 joint planes are numerous. Three sets were determined, 

 the directions being K 23° W., K 36° W, and K 77° W. 



At one point only was the breccia seen in contact with 

 the Utica (see X on map fig. 1.). The contact is a bree- 

 ciated one, the shale being broken up into angular frag- 

 ments with the interstitial spaces filled with a yellowish 

 white crystalline dolomite, which dissolves out leaving the 

 shale in relief. Part of this shale has in some way been 

 altered to hornstone. The contact is not sharp, but there 

 is a regular transition from the normal shale through the 

 brecciated facies to the breccia proper. 



Beside the ordinary inclusions, the breccia holds two 

 very large masses of limestone, which merit special men- 

 tion. These occur on the north-east side of the island. 

 The south exposure is lenticular in shape, and is cut by a 

 dyke which has been subsequently faulted. It has an 

 area of about 100 square feet. The rock is a fine grained, 

 light grey, friable limestone. The north exposure is 

 200 feet in length, and is a dark grey fine grained semi- 

 crystalline limestone, which is somewhat bituminous. 

 It has been brecciated along the contact with the breccia, 

 and the angular fragments have been cemented by a paste 

 which differs in composition from the limestone. On a 

 weathered surface this matrix stands in relief forming a 

 complicated network, which shows the most minute detail 

 in structure. Both limestones are fossiliferous, being 

 particularly rich in Brachiopods. These limestone occur- 

 rences were opened up by blasting, the material obtained 

 being forwarded to Dr. H. S. Williams of Yale University, 



