Preliminary Report on the Geology of the Common Roads of the United States

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U.S. Government Printing Office, 1895 - Roads - 52 pages
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Page 273 - This effect is due to the tendency of water which contains iron to lay down that substance and to take lime in its place when the opportunity for so doing occurs. Such gravels are termed ferruginous. They are commonly found in a somewhat cemented state, and when broken up and placed upon roads they again cement, even more firmly than in the original state, often forming a roadway of very good quality. When no gravel...
Page 272 - ... of broken stone. There is also an absence of dust or other material to serve as a binder, and even if such binding material is furnished it is difficult to effectively hold the rounded and polished surface of the pebbles together. In certain deposits of gravel, particularly where the pebbly ^matter is to a greater or less extent composed of - limestone, a considerable amount of iron oxide has been gathered in the mass. This effect...
Page 272 - ... in the bonding power of the material. In texture the clay is rather coarse, and breaks up readily. BOG IRON ORE. Bog iron ore occurs in various parts of the State, but usually in thin deposits and of local extent. It has been stated by Shaler, (US Geological Survey, 15th Ann.
Page 280 - So far as I am aware, no experiments have been made in this direction.
Page 274 - These materials were borne southward, either contained in the slow-moving ice or hurried along by the violent currents of water which swept forward to the margin of the field.
Page 281 - ... roads, and on the most of those made of gravel as well, the effect of the penetration of water in loosening the mass of the roadbed is serious, in most cases up to the margin of disaster.
Page 272 - ... The variety of such stone which is known as dolomite commonly affords a better rock than calcite, or ordinary limestone.
Page 276 - ... the weather have decayed by a process of leaching, which in many cases has removed hundreds of feet of strata from the surface of the country.
Page 295 - ... No absolute control is needed other than the road followed or towns passed over. The photographs will show the width, and possibly the character of the road; the bridges, whether standing or destroyed, width of streams at crossings, fords along side of roads and the general nature of the topography for a distance of from 1 to 3 miles on . each side of the road. Flying can be done in the morning, photographs developed and mounted in the afternoon and ready that night for issue to advance guard...
Page 271 - Quartz, when it is found, as is sometimes the case, in large veins in which it has been deposited from water at depths below the original surface, often affords a tolerable material for macadam purposes. Owing to the very angular forms which the material assumes when crushed, it mats well together. The bits, however, are not really cemented into a mass, for the dust, unlike that...

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