1867.] 245 [Agassiz. 



but wc can find no trace wliatevei- of any anticlinal axis at tlicpc two 

 ravines, which are about two miles apart ami present identical fea- 

 tures. One of these ravines commences in the property of the St. 

 Louis IMining Company, Section ID, Township 56, Range 32 north, 

 about one and one-half miles south of Calumet. An old adit entering 

 from the ravine into an abandoned lode plainly shows that the formation 

 still dips about 42° north. About six hundred feet further east, follow- 

 ing the ravine where the dip of the Ibrmation does not change, we 

 come upon the bed of chloritic rock forming the junction of sandstone 

 and trap, and about one hundred feet further down the ravine we 

 come upon horizontal beds of sandstone reaching to the very crest of 

 the ravine, here about one hundred feet deep, plainly showing that 

 the sandstone rests unconformably upon the trap which has a dip of 

 42° north. These same horizontal beds can be traced the whole length 

 of the ravine, for a distance of over one and a half miles. The same 

 is the case at the Douglass Houghton Creek in Section 36, Township 

 56, Kange 33 north, where the creek winds its way through a deep 

 ravine cut out of the sandstone, and at the junction of the sandstone 

 and trajj, falls a depth of one hundred and seventy-two feet. The chlo- 

 ritic bed is well developed on the south side of the creek, Avhile the 

 north side is more greenstone, and all along the whole length of the 

 ravine up to the falls, a distance of one and one-half miles, the hori- 

 zontal beds of sandstone are readily traced, dipping slightly north 

 near the falls, and being horizontal at the ojjening of the ravine into 

 Torch Kiver valley, plainly showing that they rest unconformably 

 upon the trap range. On examining this sandstone more carefully, 

 we find that the strata are made up of alterrating layers of sandstone 

 of reddish or yellowish grain, an<l of beds of loose sandstone containino^ 

 boulders; some of the beds of boulders resembling what is common 

 on seashores as a mixture of mud and shingle. On breaking open 

 several of the small boulders taken in silii from the beds we find that 

 they consist mostly of reddish trap, but fi'equently we come across per- 

 fectly well waterwoi-n boulders of greyish trap containing amygdales, 

 identical with the trap of the copjier range a short distance west from 

 these beds of sandstone, plainly showing that the sandstone was depos- 

 ited upon the shores of the ridge of trap forming Keweenaw Point, 

 and has not been uplifted by it as is stated by Foster and Whitney. 

 The case is totally different with the sandstone north of the range that 

 lies conformably upon the trap, but the sandstone of the southern side 

 of the mineral range in the vicinity of Torch Lake is plainly of a dif- 

 ferent age, lying, as it does, unconformably upon the former. I shall 

 be able, I trust, to make a more careful examination of this subject, 

 and by examining a greater number of points, the discrepancy between 

 the observations of Messrs. Foster and Whitney and mine may be 



