. The copper-bearing rocks of lake Superior / by Roland Duer Irving. Geology; Geology; Copper ores; Copper ores. EOCKS AT MOUTH OP TEMPEEANCE ElVEE. 325 "Two Islands," which are columnar rocks with the outline of Fig. 26, and of the mouth of Temperance Eiver, are also very Fig. 26.—Profile of island at mouth of Two Islands Eiver. The last-named place is possibly the most interesting of all. A short distance from its mouth the river makes several falls, the first one into, the rest along the course of a narrow gorge, which sometimes reaches 50 feet in depth, but is so na
. The copper-bearing rocks of lake Superior / by Roland Duer Irving. Geology; Geology; Copper ores; Copper ores. EOCKS AT MOUTH OP TEMPEEANCE ElVEE. 325 "Two Islands," which are columnar rocks with the outline of Fig. 26, and of the mouth of Temperance Eiver, are also very Fig. 26.—Profile of island at mouth of Two Islands Eiver. The last-named place is possibly the most interesting of all. A short distance from its mouth the river makes several falls, the first one into, the rest along the course of a narrow gorge, which sometimes reaches 50 feet in depth, but is so narrow that in places one can step from one to the other of the overhanging walls. The gorge is a succession of well-smoothed pot- holes broken into each other. There are displayed here a number of very thin layers, the massive columnar portions often not exceeding two to four feet, and the very strongly developed amygdaloids running even below these figures. A number of these beds have very plainly marked basal amygdaloids, with relatively sparse spike am5^gdules. At two or three hori- zons, streaks of red sandy shale were noticed between one of these amyg- daloids below and a massive layer above. The detrital matter is often in mere films, and at times is entirely absent. In places it is found to have aggregated in irregularities of the underlying amygdaloid, when for a short. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Irving, Roland Duer, 1847-1888. Washington, Govt. Print. Off.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectgeology, bookyear1883
