306 THE MARQUETTE IROX-BEAEING DISTRICT. 



is a belt of red graywacke. In it slatiness and schistosity have developed. 

 The slate is folded into minute crinkles, and in places cross -folded by 

 east-west pressure. It is also fractured, and the cracks and veins are filled 

 with cherty or vein quartz. This belt, on account of its uniform character 

 and schistosity, macroscopically resembles closely the schists of the Kitclii 

 formation. South of the belt of graywacke is a broad belt of reddish and 

 greenish slates, interstratified with occasional beds of quartzite and cherty- 

 looking quartz. In this part of the formation, in a single ledge, black slate, 

 red slate, novaculite, fine-grained red quartzite, and cherty quartzite may 

 be seen regularly interstratified. As a result of the movements, the slates 

 in many places take on a rather crystalline aspect. The whole is usually 

 veined with white quartz and cherty quartz, and altogether the rocks have 

 a very crystalline aspect. At one place a stratum of slate abuts directly 

 against the quartzite to the west, showing that there is here a minor trans- 

 verse fault. 



The southernmost exposures of the formation are in sec. 32, where 

 the belt is the broadest, and they are vitreous quartzites; and here occur 

 peculiar rocks, which at first sight were taken for conglomerates, having 

 a quartzite matrix and quartzite pebbles, the matrix being stained by oxide 

 of iron. When this belt was closely examined the peculiar conglomerate 

 was found to be dynamic. Under the stress to which the rock was sub- 

 jected it fractured in a spheroidal manner, each of the spheroids at first 

 sight appearing to l)e a pebble, but close examination shows that many of 

 them are attached at some place to the matrix. This conglomeratic rock, 

 when traced along the strike, is found to become less and less fractured, 

 and to grade into the oixlinary quartzite. 



The whole set of beds making iip the bluffs has a rather uniform dip 

 to the south, the dip perhaps being somewhat higher on the northern side, 

 near the contact with the green schists, than farther south. The dips 

 observed vary between 57° and 70° to the south. It is perhaps possible 

 that the lower bed of conglomerate and quartzite represents the Mesnard 

 formation; the red graywacke, the Kona dolomite; the interstratified slates, 

 graywackes, and quartzites, the Wewe slate; and the upper quartzite, the 



