Bulletin, Issues 448-454U.S. Government Printing Office, 1911 - Geology |
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Page 19
... locality . Talus deposits cover the lowest mountain slopes and reach their greatest development at the bases of large porphyry exposures and limestone cliffs . In this connection it should be said that the occur- rence of a small ...
... locality . Talus deposits cover the lowest mountain slopes and reach their greatest development at the bases of large porphyry exposures and limestone cliffs . In this connection it should be said that the occur- rence of a small ...
Page 23
... locality . The McCarthy Creek section gives an almost equally good chance for measurement , and the results are the same as on Nizina River . A section north of Chitistone River gives a greater thickness than 3,000 feet , but as in this ...
... locality . The McCarthy Creek section gives an almost equally good chance for measurement , and the results are the same as on Nizina River . A section north of Chitistone River gives a greater thickness than 3,000 feet , but as in this ...
Page 24
... locality . In most cases specific identifications have not been possible , but this does not lessen the accuracy of ... localities . Dr. Stanton says of them : The fossils from the Chitistone confirm the recent determinations of that ...
... locality . In most cases specific identifications have not been possible , but this does not lessen the accuracy of ... localities . Dr. Stanton says of them : The fossils from the Chitistone confirm the recent determinations of that ...
Page 28
... localities . It begins to be conspicuous in the transition beds at the base of the shale ( see Pl . IV , B , p . 18 ) ... locality for the formation . This is not only the largest area of the shales examined but it also shows a greater ...
... localities . It begins to be conspicuous in the transition beds at the base of the shale ( see Pl . IV , B , p . 18 ) ... locality for the formation . This is not only the largest area of the shales examined but it also shows a greater ...
Page 29
... locality have a horizontal position and are probably less distorted by folding than they are to the north- west . This measurement is considered the minimum and probably much less than the true thickness , for some of the shale has ...
... locality have a horizontal position and are probably less distorted by folding than they are to the north- west . This measurement is considered the minimum and probably much less than the true thickness , for some of the shale has ...
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Common terms and phrases
30 feet Alaska amphibolite anticline basin biotite Bonanza Bowlder calcite camp cent chalcocite chalcopyrite Chitina Chitistone Chititu Clarion conglomerate copper corner of sec County Cretaceous deposits dikes diorite distance district drilled erosion exposed fault feet east feet north feet south feet west feldspar flows Foxburg Foxburg quadrangle geologic gneiss gold granite graphite gravels greenstone hills hornblende igneous inches intrusion iron post stamped Jurassic Kittanning Koyuk Koyuk River limestone Llano locality located lower magnetite McCarthy Creek metamorphic minerals mining Mountain Nikolai Nizina northeast northwest Nulato occur outcrop oxide Paleozoic pegmatite places pre-Cambrian present probably prospect pyrite quartz region reported ridge River road rock glaciers Salt Creek sandstone schistose schists sedimentary sediments Seward Peninsula shaft shale Shannon sandstone side southeast corner southwest stream structure surface Survey Third sand Township Triassic U. S. Geol upper valley vein vicinity
Popular passages
Page 11 - I), 3J inches in diameter and one-quarter inch thick, having a 3-inch stem, which is cemented in a drill hole in• solid rock in the wall of some public building, a bridge abutment, or other substantial masonry structure. The second form (F, PI.
Page 11 - ... level. Mean sea level is the average height of the water, all stages of the tide being considered. It is determined from observations made by means of tidal gages...
Page 11 - I). The numbers stamped on the bench marks described in the following pages represent the elevations to the nearest foot, as determined by the levelman. These numbers are stamped with T^g-inch steel dies on the tablets or post caps, to the left of the word "feet.
Page 28 - FORMATION The Carbondale formation which extends from the top of the Pottsville to the top of the Herrin coal (No. 6), is about 225 feet thick in the vicinity of Carlyle. A bed of sandstone which in the lower 50 feet of this formation varies in thickness from 10 to 40 feet or more, is almost everywhere present. This rock generally contains salt water and hence is commonly included by the drillers...
Page 89 - At one place a vug was found large enough for a man to enter, lined with " smoky " quartz crystals reaching 1,000 pounds or more in weight. This would seem to indicate that the pegmatite had been intruded in a pasty or semifluid condition and that the vugs represent the spaces occupied by segregated water that was squeezed from the magma as the minerals took their final solidified form. The feldspar is an intergrowth of microcline and albite, of a brownish flesh color, beautifully fresh, and occurs...
Page 96 - ... which weighed two ounces and one dollar, besides other small pieces. Others of his party found good prospects, but none of the company had come for anything more than to ascertain the truth or falsity of the reported glad tidings and therefore were not prepared to remain and work for want of the necessary provisions and tools, but were compelled to return to La Laguna, a settlement some twenty miles above Fort Yuma, on the Arizona side of the Colorado. After their arrival at La Laguna, and report...
Page 11 - The office adjustment of the notes and the reduction to mean sea level datum may so change some of the figures that the original markings are 1 or 2 feet in error. It is assumed that engineers and others who have occasion to use the bench-mark elevations will apply to the Director of the United States Geological Survey, at Washington, DC, for the adjusted values, and will use the markings as identifications numbers only.
Page 93 - ... to the west side of the ridge. The richest ore, consisting of large masses of chalcocite with some included limestone, is encountered at a distance of 90 feet from the tunnel's mouth and continues for a distance of 21£ feet as measured in the roof. There are smaller bodies of chalcocite, however, for a distance of 10 or 15 feet on either side of the main ore body. About 115 feet from the entrance to the tunnel a winze 33 feet deep was sunk in the ore, and from the bottom a drift zigzags northward...
Page 11 - Mean sea level is the average height of the water, all stages of the tide being considered. It is determined from observations made by means of tidal gages placed at stations where local conditions, such as long narrow bays, rivers, and like features will not affect the height of the water. To obtain even approximately correct results these observations must extend over at least one lunar month, and if accuracy is desired they must extend over several years.
Page 130 - Sheridan and Bear creeks the gold is mostly on bed rock, differing in this respect from that on Cub Creek, where it is found throughout the whole thickness of the 2 feet of stream gravel; on the other hand, gold from Bear and Cub creeks is light and flaky while that from Sheridan is heavy. All the gold is bright yellow in color, assaying $19.20 to the ounce. A little "white iron" pyrite is present ind also an abundance of black sand which is entirely removed by the magnet.