of ^Lake Superior. 235 



in bundles of fibres — usually both it and the stilbite (red and ob- 

 scurely crystallized") are imbedded in, or superimposed on calc- 

 spar. Here the green earth becomes compact, of conchoidal 

 fracture and disseminated in fine grained dark amygdaloid, which 

 in other parts of the same ridge becomes paler, and contains the 

 ordinary agates and calcspars. The beaches of this district have 

 many small bowlders of shell limestone, probably of the same age 

 with that of Derbyshire, of amygdaloids with copper pyrites and 

 the green carbonate of that metal. I saw among them one mass 

 of radiated quartz. It is a geode : — on breaking it the fractured 

 surface presented three centres, from which imperfect crystals 

 diverged in a stellular form. 



The trap of the Marmoaze, whose situation and nature have now 

 been sketched with all the fidelity my opportunities would allow, 

 is succeeded by white granite. A ravine at the centre of the bay 

 next on the north separates these two rocks ; the latter being a 

 high escarpment, while the former, throughout the south side of 

 the bay, is in low ledges separated by sandy beaches. This granite 

 now occupies the north shore for 58 miles of the canoe route. 

 Huggewong Bay is an example of the style of country it produces. 

 It is white, or nearly so, the feldspar being white or pale red, and 

 predominating; the quartz white, and the mica scanty and in 

 small black plates. As well as I recollect, there always is a lit- 

 tle hornblende disseminated, and commonly a large quantity. 

 Much of this granite is of moderately-fine grain ; but now and 

 then it is slightly porphyritic. It contains very numerous contem- 

 poraneous masses of a very large porphyritic kind, from one to 

 fifty yards in diameter, sending off trunks which ramify in all 

 directions, and frequently unite with others of these masses; and 

 as frequently arc lost in the imbedding rock. This form of granite 

 consists almost exclusively of feldspar and quartz, both white, 

 the crystals of the former being from six to eight inches in 

 diameter. By the gradual diminution, in many cases, of these 

 crystals, and of the fragments of quartz, towards the outside of 

 these knots and branches, a slow transition is effected into the 

 granular granite. Both these species are traversed indifferently by 

 R2 



