388 



DESCRIPTION OF THE COUNTRY BORDERING 



5. Same as Nos. 105 and 10G, highly metamorphosed ; amygdaloidal, the cells being filled with calcite, 

 laumonite, and other minerals. (Nos. 107, 108, 109.) This rock loses its distinctly stratiform character, 

 and the shales on which it rests (Nos. 110, 111, 112) pass into a highly metamorphosed rock like No. 100, 



6th. Trap ridge, bearing east 15° north. This is, probably, the ridge which comes to the lake-shore 

 above, where it exhibits a columnar structure, and has been set down as basaltic rock. Above this point, 

 the walls between which the creek runs are composed of metamorphosed shales and sand-rock (Nos. 107, 

 108, 109), which continue for a long distance, with occasional exposures, in the bed of the stream, of Nos. 

 110, 111, 112. Above the last exposure of these rocks, the bed of the creek is literally filled with boul- 

 ders of No. 115. 



The beds resting against the greenstone are highly brecciatecl (No. 116), and con- 

 sist, almost entirely, of fragments of Nos. 107 and 110. The exposures at this 

 place indicate very clearly, I think, that the greenstone was erupted about the be- 

 ginning of the deposition of the red sandstones and sandy shales, as the thick breccia 

 which underlies them is composed entirely of the lower beds of the sand-rock and 

 shales, and shows every evidence of having been the result of violent disturbance, 

 while the overlying beds, which are soft and easily fractured, exhibit no signs of 

 having been disturbed since their deposition, except, perhaps, in an increase of dip, 

 which may have been occasioned by gradual upheaval or subsidence, long posterior 

 to the period of eruption of the greenstone. The sand-rock beds in this neighbour- 

 hood are nearly all ripple-marked. The highest ridge measured here was four hun- 

 dred and eighty-five feet above the lake-level. 



In the large bay beyond, there is an exposure of metamorphosed sand-rock and 

 slates, in which the sand-rock is found to rest unconformably on the slates, as shown 

 in the subjoined figure. The slates dip to the northwest, at a high angle, and rest 

 against a heavy dike of greenstone. 



e h a 



a. Greenstone, b. Slates, c. Metamorphosed sand-rock. 



Between this place and Bitobigungk Bay, the lake-shore is made by low expo- 

 sures of metamorphosed rocks, with an occasional exposure of trap at the small 

 promontories. 



The rock (No. 633), which makes Bitobigungk Point, as well as the bay above, 

 bears east and west. It is very regularly jointed, and forms three, four, and five- 

 sided columns. On the large exposure of this rock, which slopes into the Lake 

 from the south side of the bay, are numerous grooves and scratches. There are, at 

 least, two sets, one having an east-and-west direction, and the other bearing west 

 25° south. 



While the body of the rock is very ferruginous, and of the colour of iron-rust, it 

 is of a light-gray colour in the joints, which colour extends into the body of the 

 rock for an inch or more from the joints. This discoloration has been attributed 



