248 On the Geography and Geology 



and stretching to the middle of the capacious bay N.W, of 

 Peek Island. This interval is about twenty-two miles long by the 

 canoe route. I have not examined acccurately this rock nearer 

 than two miles and a half from where I last observed the green- 

 stone. Here it emerges from under alluvion, as an unstratified 

 mound of small porphyritic structure and composed of black horn- 

 blende with high lustre, and of feldspar in muddy green translucent 

 crystals. It is penetrated by veins of similar materials, but very 

 largely crystallized. The next opportunity for observation occurred 

 three miles westward, at the cluster of casque-shaped isles. They 

 are of indisputable sienite, consisting solely of brick-red feldspar, 

 and light green hornblende, the mass being small porphyritic, 

 passing into large granular, and without stratification. The 

 neighbouring country, I am nearly certain from distant inspection 

 is sienitic. My next landing-place was at the promontory, three 

 miles N.E. from Peek Island, almost a naked heap of mounds 

 of sienite, closely compacted together, and very obscurely stra- 

 tified In E .S.E. and EbN. directions." It is brownish red, and 

 porphyritic, with the black hornblende, sometimes arranged con- 

 fused in long crystals. The feldspar is red. There is not a vestige 

 of disseminated quartz in it. It is often very ferruginous; and 

 then is bluish black and brown ; and greatly disintegrated. The 

 most largely-crystallized sienite of this headland has many small 

 geodes of crystals of quartz, feldspar, hornblende, and calcspar. 

 Purple fluor-spar occurs in the fissures of the smaller grained 

 species. INIr. Bayfield found here, chlorite in veins, associated 

 with white calcspar. This sienite contains very large irregularly 

 shaped beds of black compact greenstone ; which it also traverses 

 in large and small ramifications. It has masses many yards 

 square, of very green hornblende, with white feldspar, which falls 

 out on exposure to weather, and leaves a remarkably ragged 

 surface. The shores of this promontory abound in fragmer\ts of 

 blue and brown limestone, now and then four and five pounds in 

 weight each, and containing trilobites, orthoceratites, 8fc. 



On the Cape opposite to Peek Island, the sienite becomes 

 redder, and rather compact and slaty ; but I did not discover any 



