The Geologic Time Classification of the United States Geological Survey Compared with Other Classifications, Accompanied by the Original Definitions of Era, Period and Epoch Terms

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U.S. Government Printing Office, 1925 - Geological time - 138 pages
 

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Page 68 - ... Waverly as a geological term dates back to 1837 and 1838, during the first geological survey of Ohio. After describing the "Argillaceous slaty rock, or shale stratum," (Ohio shale), Briggs states that "Superimposed upon the stratum above described occurs a series of alternations of sandstone and shale As some of the most beautiful stones that have been obtained were quarried at Waverly, we may, for the present, denominate these rocks the Waverly sandstone series."1 Briggs gave the "Conglomerate,"...
Page 42 - Pliocene epoch before alluded to, there are one hundred and ninety-six, whereof one hundred and fourteen are living, and the remaining eighty-two extinct, or only known as fossil. As there are a certain number of fossil species which are characteristic of the Pliocene strata before described, so also there are many shells exclusively confined to the Miocene period. We have already stated, that in Touraine and in the South of France near Bordeaux, in Piedmont, in the basin of Vienna, and other localities,...
Page 77 - As it is now acknowledged that the rocks along the Hudson river valley, to which the name ' Hudson River group ' has been applied, belong, as long maintained by Prof.
Page 62 - The carboniferous system is surmounted, to the east of the Volga, by a vast series of beds of marls, schists, limestones, sandstones and conglomerates, to which I propose to give the name of "Permian System...
Page 106 - Ogishke conglomerates in the central parts of the district, especially >n the vicinity of Snowbank lake, but this locality was not visited by the party. In the Rainy lake district the party observed the relations of the several formations along one line of section at the east end of Shoal lake and at a number of other localities. The party is satisfied that along the line of section most closely studied the relations are clear and distinct. The Couchiohing schists form the highest formation.
Page 101 - The rocks on the Lake of the Woods, which are in the following pages referred to as " agglomerate-schists," are not basal conglomerates. They are not at the base of the series included in the schistose belt, nor are they apparently composed of water-worn fragments, derived from the rocks upon which they rest. No fragments that can be referred to the underlying granitoid Fragmentai gneisses are found included in the agglomerate-schists of the Lake of voleanic origin!
Page 85 - Group rests uncomformably upon the crystalline schists. The evidence of this is complete, for the lower sandstones and conglomerates first filled the valleys and then buried the hills of schistic rocks, and these conglomerates at the base of the group are composed of materials derived from the metamorphic hills about ; and hence metamorphism was antecedent to the deposition of the conglomerates. The plane of demarkation separating this group from the Tonto Group is very great. At least 10,000 feet...
Page 77 - ... subdivision of the Interlake Formation, but since these are not rock-stratigraphic units, we prefer to call these subdivisions intervals rather than Beds or Members. STRATIGRAPHY Stony Mountain Formation Name and Definition: The Stony Mountain Formation was defined by Dowling (1901, p. 46) as the Ordovician rocks lying between the top of the Trenton and the base of the Silurian rocks in the Stony Mountain, Manitoba area. Okulitch (1943, p. 60) determined a thickness of about 110 feet for the...
Page 36 - I shall now proceed to consider the subdivisions of tertiary strata which may be founded on the results of a comparison of their respective fossils, and to give names to the periods to which they may be severally referred. But, first, it will be necessary to explain the difference between the tertiary phenomena and those described in the last two books. In the present work all those geological monuments are called tertiary which are newer than the secondary formations, and which on the other...
Page 101 - holding pebbles and boulders, sometimes a foot in diameter, of the subjacent gneiss, from which they appear to be derived. The boulders display red orthoclase feldspar, translucent, colourless quartz, green hornblende and brownish-black mica, arranged in parallel layers, which have a direction according with the attitude in which the boulders were accidentally enclosed.

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