218 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jail. 4, 



The chlorite-slate is well characterized by its glossy-green colour, 

 unctuous feel, and wavy or even crimped lamination. At the south 

 angle of Forbes' Bay, a few hundred yards inland, these undulations 

 take on a singularly contorted form. It is difficult to conceive what 

 kind of force, or combination of forces, could have created the 

 regular succession of numerous waved zigzags, seen at this spot, all 

 of the same size (.5 inches long), and ending suddenly in gracefully 

 recurrent sweeps of lamination on a much larger scale. At this 

 place, the layers of the chlorite-slate open, and contain irregular 

 deposits many tons in weight, either of hornblende, or of very white 

 crystalline quartz. A little to the west of Point Back are veins of 

 chlorite-earth, a foot and more thick ; and there the foliations of the 

 chlorite-slate are greatly bent and crumpled. Chlorite-slate here 

 never passes into syenite, at least directly ; but is confusedly and 

 largely interleaved with it, as in Hopkins Bay. 



At Point Back, a mound or two of grey granite protrudes above 

 the marshes. 



Both the greenstone and the chlorite-slate are strictly conformable 

 with each other ; — their most common strike being E.N.E. At Cape 

 Chamberlin, and on the north side of Forbes Bay, it is a little to 

 the south of east ; the strike is to the north of east on the south 

 side of that bay, and throughout all the coast to Cape Bayfield, with 

 the exception of the south side of Hopkins Bay, in proximity to 

 syenite, where it is north-east, with a southerly dip, contrary to the 

 usual dip in Rainy Lake. The dip is often vertical, and always high. 



Third Division. — The third division commences at Point Bay- 

 field, and extends nearly over the whole eastern arm, twenty-eight 

 miles long in a direct line. The immediate shores of the lake are 

 usually morasses, except high up in the north of this arm, where 

 the country ascends at once in hills of pine-forests, or in naked 

 ridges, 500 feet high, and as white and shining as porcelain. This 

 division is characterized by the confused state of its stratified rocks, 

 especially on the west side of the arm. 



White or pale red granite is the prevailing rock, and especially in 

 the north, accompanied- by syenite*, and flanked by mica-slate and by 

 chlorite-slate and greenstone- slate, quite the same as those already 

 described. 



The strike of these three last-mentioned rocks is usually N. and 

 N.W., as at Bears Pass, Otterberry Lake, and Porter's Bay; to the 

 N.E., at Spawning River and the Manitou Rocks ; as well as to the 

 E.N.E., two miles north of Parry Strait. On the east side of the 

 Arm, the strike seldom deviates from the N.E. or E.N.E. 



B\' way of a few local details, we have to state that, from Cape 

 Bayfield to Otterberry Lake, there is a confused intermingling of 

 granite with greenstone-slate and chlorite-slate, and with three small 

 districts of coarse grey mica-slates ; one of these being a mile south 

 of Bear's Pass, and the other two near the foot of Otterberry Lake ; 

 the most northern having many flexures, and abounding in garnet 

 and staurotide. 



* I foiuid ixpiitilc in the syenite of Porter's Bay. 



