ON THE NORTHWEST SHORE OF LAKE SUPERIOR. 385 



basaltic dike, bearing east and west. From this place to the mouth of Cut Face 

 River, low exposures of metamorphosed sandstone, with alternations of trap and 

 shale beds, and, at one point, a bed of breccia beneath the shales, form the shore. 

 These rocks appear to be capped almost everywhere by a bed of No. 133. 



18. Cut Face River. — This stream is forty feet wide at the mouth. Seventy-five 

 or eighty yards up, rapids occur ; and above that point the river runs through a 

 narrow gorge with perpendicular walls, varying from twenty to fifty feet in height, 

 and from six to twenty feet in width. For the distance of three-quarters of a mile 

 above the first rapids, the water falls in a series of cascades, from five to fifteen feet 

 high, and seldom more than twenty or thirty yards apart, often much nearer 

 together. A trap ridge then crosses the river, bearing east and west. Above this 

 the rocks are exposed for more than three miles, the river still flowing through a 

 gorge. In this distance two other trap ridges cross the stream, bearing east and 

 west. Just below the highest point to which we ascended, a greenstone ridge (No. 

 119) crosses the river, bearing east-northeast and west-southwest. The bed of the 

 river where this ridge crosses is three hundred and seventy-six feet above the lake- 

 level. 



The lowest bedded rock at this place is No. 120.* In near contact with the 

 greenstone, it bears some little resemblance to syenite. Above No. 120 is a bed, 

 ten feet thick, of metamorphosed shale ; and overlying that, about thirty feet of 

 altered shaly sandstone, with beds of volcanic tufa (No. 121), which reaches to near 

 the top of the ridge, and is overlaid by a breccia composed of angular fragments 

 and rounded pebbles, which appear to be derived entirely from the shaly sandstone. 

 Over the breccia is a thin bed of greenstone, and above that clay and marl beds. 

 Between the third and fourth ridges is a small stream, in the bed of which the 

 metamorphosed shaly sand-rock, with intercalated beds of tufa (Nos. 122, 123), 

 rests on volcanic grit-beds (Nos. 124, 125). These are the same rocks seen higher 

 up stream, near the greenstone ridge, and the lower beds here as well as there have 

 a syenitic aspect. The next rock (No. 127) is a bedded trap, and near its junction 

 with the siliceous shale (No. 126) which overlies it, presents a laminar appearance. 

 Above (No. 126) is a breccia, formed of sand-rock and shales ; and over the breccia 

 (after passing the greenstone dike), comes an amygdaloid, like that described as 

 overlying the shales at other places. 



A short distance further down the river is a quartzite, which, at some points, re- 

 sembles syenite very much. It is, however, made up principally of rounded grains 

 of quartz, with some of felspar and hornblende. I consider it an altered sandstone, 

 the materials of which were derived mostly from the older granitic and hornblende 

 rocks. Some of the beds have a porphyritic appearance, in consequence of the 

 presence of small fragments of quartz (No. 128). This rock is overlaid by breccia, 

 and the breccia by shaly red sandstone, like that which occurs on Oginekan River. 

 Over the red sandstone, and over most of the rocks already named, are beds of red 

 clay and marl, from thirty to forty feet thick. 



* See Sect. 6, PI. 3, N. 



49 



