of Lake Superior. 231 



that is, north, from the lake into the woods, in ridges 10 and 15 

 feet broad, separated from each other by beach ; but a few yards 

 westward of this, they suddenly turn north-east, and then by a 

 sharp but unbroken bend they pass to the north-north-west, 

 ipaintaining that direction for a considerable breadth, with waved 

 contortions, curving backwards upon themselves, as singular as 

 those occasionally in gneiss. Near this remarkable change of di- 

 rection, nodules of this sandstone are imbedded in the general 

 mass ; and there is some indistinctness of stratification. This 

 rock is seen here for 400 yards, and is lost on the south-east in 

 shingle and sand, on the south and west in the lake, so that its 

 transition into the common form on the south side of this bay, §-c. 

 cannot be witnessed. On the north-north-west it comes in contact 

 with amygdaloid ; the junction, however, being completely ob- 

 scured by a fissure three or four yards broad, full of rubbish. The 

 sandstone near this spot is quite a breccia of its own fragments, 

 each from -J lb. to 3 lb. in weight. 



The amygdaloid extends rather more than seven miles north- 

 westward, and about three miles beyond Point Marmoaze. The 

 base of this rock is hornblende;— in fact, it is truly a greenstone 

 at 2|- miles and at 4 miles below this point, with a very few small 

 nodules of calcspar coated with green earth, or flattened agates 

 On the main and isles adjacent to Point Marmoaze, much of the 

 rock contains merely green earth finely disseminated. But by far 

 more commonly, it is quite full of almond, bean, or pea shaped 

 masses, sometimes ramose, and usually small. They are com- 

 posed of white calcspar and red zeolite*, associated or apart, the 

 latter being the rarer. These masses are both distinct and con- 

 fluent, and as they weather readily, they leave the crust of the 

 rock quite vescicular for some depth ; as much so as lava. When 

 foreign substances are not numerous, the rock, in disintegrating, 

 separates into roundish polyhedral concretions, which finally 

 resolve into argillaceous earth. The colours of the sound rock 

 arc brownish, greenish, or reddish black ; these changes taking 



• Other substances will be mentioned in tlie biijtiel. 



