Annual Report for ... with Accompanying Papers, Band 11

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Published for the Iowa Geological Survey, 1901
 

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Seite 24 - Dubuque northward, the dry shaly partings between the ledges of limestone afford material so rich in bitumen that it is easily lighted with a match; it burns freely and emits a strong -oily odor. Bituminous shale, precisely like that seen in the natural exposures, was brought up from the horizon of the Trenton in the deep well at Washington, Iowa; it has been recognized in other deep wells: the same shale, rich in bitumen, probably underlies the greater part of the state. If then a great amount of...
Seite 154 - The reason for believing that contemporaneous erosion is the correct explanation rather than faulting is that the sandstone occurs in a region where faults are infrequent and, when present, have a very small vertical displacement. Furthermore, Coal Measure shales are found lying against the sandstone and unconformable with it. Thus it seems that the area now occupied by the Red Rock sandstone was originally a place of great deposition of sand which certainly had a much greater lateral extent than...
Seite 256 - At other times its presence is indicated by the growth of some small Scirpus or other plants requiring moist ground. It would be premature at the present time to express any opinion as to the origin of this deposit. Probably it is mostly an old loess, which has been clogged up by interstitial deposition of fine ferrugiuous material through the agency of the ground water. Perhaps it is in part a fluviatile deposit, made at a time of semi-stagnant drainage, or possibly it is of varied origin, being...
Seite 27 - Not infrequently it is the public spirited men of the community who take the initiative, and. without knowledge of their own and asking no advice, but firm in the belief that the earth will yield anything desired if we only go deep enough, they proceed with the drilling of test holes on a scale involving the expenditure of thousands of dollars. The end is inevitable. It is that which invariably follows every ill-advised enterprise in which ascertained facts are ignored. The disappointment may be...
Seite 225 - The fragments are of different sizes. Some have a diameter of nearly a millimeter, and these are mingled with others of about one-fifth that diameter. Most appear elliptical in section. Some of the large fragments have a nucleus with a structure like a fragment of Stictopora. A few still larger fragments were pieces of small shells. This specimen also exhibits several small, crooked joints or fissure veins filled with pure crystalline calcite. Another specimen appeared to the unaided eye as an ordinary...
Seite 164 - Large bowlders are frequently met with in the bottom of the ravines and streams, but are seldom seen in other localities. Occasionally a ravine will be fairly filled with these bowlders as is notably the case with one in Tp. 75 N., R. XX W.,Se. i of Se. \ of Sec. 20. Here one of considerable size was found which measured three feet two inches by two feet four inches by two feet six inches. This was the largest one observed, most of them being little more than a foot in diameter. These glacial bowlders...
Seite 225 - This specimen also exhibits several small, crooked joints or fissure veins filled with pure crystalline calcite. Another specimen appeared to the unaided eye as an ordinary compact gray limestone, but was seen, under a lens, to be fragmental, consisting largely of small fusulinas, some of which were surrounded by a thin calcareous crust. These, together with finer fragmental material, were imbedded in a structureless calcareous matrix. Occasionally the fragments were welded together as if by partial...
Seite 225 - Limestone, yellowish and gray, in ledges from six inches to one foot in thickness, compact near the base, occasionally brecciated, and at times having a finely oolitic texture. A polished specimen of this rock is seen to consist of rounded and incrustated calcareous fragments embedded in a matrix of almost transparent crystalline calcite. The fragments are of different sizes. Some have a diameter of nearly a millimeter, and these are mingled with others of about one-fifth that diameter. Most appear...
Seite 47 - Hardin Harrison Henry Howard Humboldt Ida Iowa Jasper Jefferson Johnson Jones Keokuk Kossuth Linn...
Seite 220 - Three ledges of gray, somewhat compact limestone, each about a foot in thickness. These are separated by thin seams of soft marly material. The upper ledge has dark nodules of chert which contain numerous small fragmen's of organic structures.. . 3. 1. Yellow limestone of soft texture with many f usulinas, exposed 3. About two feet of the lower ledge in this section is again seen in the bed of a small creek about a quarter of a mile to the northeast of this quarry. It is here a bluish gray limestone...

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