NORTHWEST OF LAKE SUPERIOR. 



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phosed rock (No. 593), and forms in part the second point. In its course southerly, 

 it forms, I believe, the long Entry Point, which is in its line of strike, although it 

 is not discoverable in that part of its course, being covered with shingle and sand. 

 Continued still further to the south, it would cross Black River at or near the Falls, 

 where a dike of the same kind was found. The bedded rocks dip 18° southeast. 



In the second bay there are five narrow dikes, all bearing nearly north and 

 south, varying to 5° east, and of the same character as No. 592. They vary in 

 width from three to twenty feet.' A sixth narrow dike forms one side of the point 

 between the second and third bays, the remainder being made by No. 591, several 

 low exposures of which are seen in the last bay. The shore of the third bay is 

 made by No. 594, and also the point between it and the fourth one. In this bay, 

 the lake-shore is made by No. 595, which is much disturbed by the trap intrusions. 

 At the point between the fourth and fifth bays, there is a dike bearing north 5° 

 east, and in the fifth bay two dikes bearing north 5° west. 



In the easterly part of this bay are low exposures of No. 597 ; most of the shore, 

 however, is made by No. 595, in mural walls from ten to fifteen feet in height. 

 The sixth bay, which is a small one, is made by metamorphosed rocks, which are 

 much disturbed, and, in some instances, completely folded ; the axes appearing to 

 run north and south. This rock is traversed by a narrow dike of No. 592. At 

 some points the sedimentary rock appears to be overlaid by a bed of trap. The 

 next bay is the one in which is situated the mouth of Passabika River. At the 

 point above the mouth of the river is a dike of No. 598, five feet in width, and 

 causing a folding of the rock (No. 599), through which it protrudes, and which is 

 here overlaid by a bed of trap, described in the river section. 



3. Passabika River. — The first rock of the series at the mouth of this river is a 

 bedded trap (No. 597), overlying No. 400, on the west side of Passabika Bay. 

 This last rock forms the left bank of the river for a short distance, where it is found 

 to rest on a metamorphosed siliceo-calcareous shale (No. 401), dipping east, at an 

 angle of 17°. The next rock below this is a breccia, composed mainly of fragments 

 of altered sandstone and clay slate, and has the appearance of having been cemented 

 under the influence of heat, which brought the materials into a state of incipient 

 fusion. This rock continues up to the first fall, which is about a quarter of a mile 

 above the mouth. 



The water falls over a trap dike, bearing north 5° east. Just above this fall the 

 river forks ; and the section given from this point is on the west branch. 



The first rock above the dike is the overlying trap (No. 597) seen at the lake- 

 shore. About two hundred yards above the junction of the streams is No. 401, 

 with about ten feet of compact, regularly-bedded, argillo-calcareous shale (No. 402), 

 intervening between it and the trap-bed. No. 402 dips to the east at an angle of 

 14 1°, and is highly metamorphosed and amygdaloidal. It becomes still more so as 

 the stream is ascended, and finally gives place to a bed of reddish-gray, basaltic- 

 looking rock (No. 403). Where this rock underlies the amygdaloid, there is a fall 

 of forty feet in sixty yards, and the dip is to the east, at an angle of 20*°. A few 

 yards higher up stream the dip changes to the southeast, and decreases to 6° ; and 



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