388 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
7. Red quartzite, interstratified with masses of greenstone; the quartzite is in 
general granular and of moderately fine texture, but it occasionally be- 
comes a fine conglomerate. The color is sometimes only a light tinge 
of red and at others a decided red, seemingly derived from minute and 
thickly disseminated spots or from a diffused tinge of an orange-red, 
probably due to the presence of iron, but the spots are sometimes of a 
larger size, and so arranged as to give to the rock a speckled aspect. 
The rock is in general thick bedded; some of the beds shew oblique 
elementary layers, or what is commonly called false bedding, and the 
surfaces of other beds display well-defined ripple-marks; masses of 
greenstone are interstratified in the deposit, some of them of great 
thIiCkMeSs;; occu esse eee eee eee eect itis hoes ise ace ea uaetas 
8. Red jasper conglomerates. The rock is sometimes a moderately fine grained 
white quartzite, often with a vitreous aspect, but it very commonly 
becomes coarse grained and assumes the character of a conglomerate, 
the pebbles of which vary from the size of a duck-shot to that of 
grape and canister; these pebbles are almost entirely either of opaque 
white vitreous quartz or various colored jaspers; some of them are 
lydian stone, some hornstone, and other varieties, and many of them 
are banded, shewing their derivation from a more ancient stratified 
rock. The pebbles are often displayed at the top or bottom or in the 
middle of fine grained beds; they are sometimes arranged in thick 
bands, and blood-red jaspers often predominating in a nearly pure 
white base produce a brilliant, unique, and beautiful rock. Consider- 
able masses of greenstone are intercalated in different parts of the 
PLOUPs -ssiitie ba SSee JS eee ee ee Oe eo eee 
9. White quartzite, very frequently of a vitreous Peer in Gonna mente 
thicknesses of the rock the bedding appears sometimes to be so com- 
pletely obliterated, and the whole mass presents so great a uniformity 
of appearance, that it becomes quite impossible to ascertain the dip 
or strike, or to distinguish joints from beds, but in other parts massive 
beds are separated by thin siliceous layers resembling chert, and green- 
stones occur intercalated between different masses of the deposit, . .-. 
10, Yellowish chert in thin and very regular beds, interstratified with layers 
of green, buff, and gray siliceous limestone, and green and pale drab 
compact siliceous slate, with a stratum of red and yellowish fine 
grained sandstone at the bottom, === =). 2 0 22s ae rte 
11. White quartzite, frequently of vitreous aspect, and occasionally mottled 
with lead-gray patches, . 
2. Yellowish chert and impure limestone, similar in its general aspect to the 
previous chert: band}. 25 52h. 2.2 sae cies oe es ee ee een ieee ees 
13. White quartzite imperfectly examined,.......-...-. gob dos cttis Se eta eee 
Feet. 
2, 800 
2,150 
2,970 
