ROCKS EXPOSED ON ECHO LAKE. 119 



half miles the talus (numbers 8 and 9) is composed of fragments of dark, 

 hard, greenish slates and argillites, among which are many enormous blocks 

 of a conglomerate closely similar to the vertical conglomerates on the shore 

 of Thunder bay, Lake Superior, with the fractures passing through the 

 pebbles. The hill (number 9), however, is essentially a reddish, vitreous 

 quartzite. Neglecting the results of observations made in traveling about 

 two miles up the river entering at the head of the lake, we pursue a traverse 

 nearly north through the wilderness. Ascending the first hill (number 10), 

 the lower surface is covered with angular fragments of reddish and felsitic 

 quartzite, succeeded by sericitic quartzose schist and many large masses of 

 slate conglomerate, of which the slate is dark greenish, considerably warped 

 and twisted, and the pebbles partially rounded, reddish, mostly of feldspar, 

 with some of quartz. Some of the pebbles are smoothly rounded. Near 

 the top of this hill (number 10), which is about 125 feet high, the slate con- 

 glomerate is in place, apparently standing about vertical. It is knobbed 

 and rough, and strikes about east and west. 



Climbing the next hill (number 11) and still maintaining a general north- 

 erly direction, many sharp, angular fragments of felsitic quartzite are en- 

 countered, and some greenish argillitic matrix of slate conglomerate. Toward 

 the summit are beds of felsitic quartzite, standing vertical, and striking north 

 70° west and north 60° west. There are also many rounded bowlders of red 

 jaspery quartzite, with black flint and glassy quartz. With these are frag- 

 ments of hard, bluish, non-fissile, argillitic slate, with laminae of felsite, and 

 also fragments of petrosilex. 



On the summit of the third hill (number 12), about 400 feet above the lake, 

 is seen vertical, knotted, serico-argillitic schist, woven into meshes by half- 

 inch thick quartz veins. In this vicinity occur outcrops of hematite, ochre- 

 ous on surface and joints, but solid, and consisting of compacted lamellse, re- 

 mote from surfaces. The country rock here is quartz, and the iron occupies 

 little nests in it. The formation, however, seems to be originally a greenish 

 schist, which has been cut by quartz vein's in such number and magnitude 

 as to have mostly replaced the schist in some places, though in others con- . 

 siderable areas of the schist remain. Down west from the summit of this 

 hill, 50 feet, is another occurrence, with the gnarled greenish slate more 

 abundant. The formation dips about ^o° southwesterly. A hundred and 

 fifty feet beyond, the slate is comparatively free from quartz, but contains 

 courses of granulite pebbles. The slate formation shows an even surface, 

 with lines of bedding very distinct, and running north 55° west. Here and 

 there the pebbles appear at the surface, exactly as in Minnesota. In this 

 place the slate is argillitic and not gnarled. 



Going one-eighth of a mile east, we arrive at a huge mass of diorite with 

 bright black hornblende and red feldspar. This is just west of the highest 

 peak (number 13). 



