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acid amount anthracite antimony appears Arizona arsenic assay average beds bottom calcination California carbonate Carboniferous cent chemical Chestatee River chloride coal contain copper cost Cretaceous crevice crystalline crystals cupel Dahlonega deposits depth district ditch Edward Hitchcock employed explorations extended extraction formation formed fossils furnace galena geological geologists gold hearth heat Hill hundred feet inches iron labor Lake Superior lead lime limestone locality lode Marcou mass matts melted metal metamorphic miles mineral Mining Company mountains nearly observed obtained occur opening operation orthoclase ounces oxide oxyd porphyry portion precipitation present probably produced pyrites quantity quartz region Report reverberatory furnace rich river roasting rocks salt sandstone Santa schists shaft shales silver mines slag smelting Sonora specimens steel strata sulphate sulphur sulphuret surface temperature Tetradymite thickness tion tons upper Valley vein vicinity Virginiatown washed yield zeolites zinc
154 페이지 - On this difficult and mysterious subject a work will very shortly appear, by Mr. Charles Darwin, the result of twenty years of observation and experiments in Zoology, Botany, and Geology, by which he has been led to the conclusion, that those powers of nature which give rise to races and permanent varieties in animals and plants, are the same as those which, in much longer periods, produce species, and, in a still longer series...
154 페이지 - Geology, by which he has been led to the conclusion, that those powers of nature which give rise to races and permanent varieties in animals and plants, are the same as those which, in much longer periods, produce species, and, in a still longer series of ages, give rise to differences of generic rank. He appears to me to have succeeded, by his investigations and reasonings...
152 페이지 - I have thus failed to obtain satisfactory evidence in favor of the remote origin assigned to the human fossils of Le Puy, I am fully prepared to corroborate the conclusions which have been recently laid before the Royal Society by Mr. Prestwich, in regard to the age of the flint implements associated in undisturbed gravel, in the North of France, with the bones of elephants at Abbeville and Amiens. These were first noticed at Abbeville, and their true geological position assigned to them by M. Boucher...
373 페이지 - ... of iron and manganese, were brought in contact with the fluid metal, during the process, and the quantity of phosphorus was thereby reduced. Thus many months were consumed in laborious and expensive experiments ; consecutive steps in advance were made, and many valuable facts were elicited.
153 페이지 - Somme, in an area fifteen miles in length. I infer that a tribe of savages, to whom the use of iron was unknown, made a long sojourn in this region ; and I am reminded of a large Indian mound, which I saw in St.
97 페이지 - Gash veins may cross the strata at any angle ; but are limited to one particular group of strata, and are peculiar to the unaltered sedimentary rocks. True veins are aggregations of mineral matter, accompanied by metalliferous ores, within a crevice or fissure which had its origin in some deepseated cause, and which may be presumed to extend for an indefinite distance downwards.
85 페이지 - Post 8vo. 8s. 6d. (FC) Principles of Athenian Architecture, and the Optical Refinements exhibited in the Construction of the Ancient Buildings at Athens, from a Survey. With 40 Plates. Folio. 61. 5s. PERCY'S (JOHN, MD) Metallurgy; or, the Art of Extracting Metals from their Ores and adapting them to various purposes of Manufacture.
151 페이지 - Faleoner, of the Brixham Cave, must, I think, have prepared you to admit that scepticism in regard to the cave-evidence in favour of the antiquity of man had previously been pushed to an extreme.
153 페이지 - ... feet above the present level of the Somme, for the deposition of fine sediment, including entire shells, both terrestrial and aquatic, and also for the denudation which the entire mass of stratified drift has undergone : portions having been swept away, so that what remains of it often terminates...
153 페이지 - ... besides being covered by a newer unstratified drift. To explain these changes, I should infer considerable oscillations in the level of the land in that part of France ; slow movements of upheaval and subsidence, deranging, but not wholly displacing, the course of the ancient river.