Elements of GeologyA.S. Barnes & Company, 1849 - 332 páginas |
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Términos y frases comunes
abound accumulations agency alluvial ammonite ancient argillaceous basalt beds bituminous bones calcareous carboniferous chalk chiefly clay clay-slate coal measures coast colour composed composition containing copper coral crustacea debris deposits depth diluvium districts dry land earth elevated estuaries existing extensive feet fishes fissures formation fossil fresh-water geological reasoning geologists geology globe gneiss gold granite grauwacke gravel greenstone gypsum heat hornblende igneous rocks iron islands lakes lava layers lead lime limestone marble marine marls mass matter metals mica mica schist miles mineral mountain limestone numerous occur ocean old red sandstone oolite organic remains petrifaction plains plants and animals porphyry present primary produced quartz range reefs region rivers salt sand schist secondary shales shell-fish shells shores silt silurian silver slate soil species springs stone strata stratified structure subterranean sulphur surface term terraces terrestrial tertiary strata texture thickness tion trachyte valleys variety vegetable volcanic wealden
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Página 240 - ... invisible. These animals are of a great variety of shapes and sizes, and in such prodigious numbers, that, in a short time, the whole surface of the rock appears to be alive and in motion. The most common...
Página 245 - The growth of coral is by no means rapid ; for objects long submerged have been dredged up merely covered with a thin incrustation. It is stated in Captain Beechey's Expedition to the Pacific, that no positive information could be obtained of any channel having been filled up by coral within a given period, and that several reefs had remained for more than half a century at about the same depth from the surface. By others, it has been estimated that the increase of a reef is generally from four to...
Página 240 - ... the tide reaches every day, it is found to be full of worms of different lengths and colours, some being as fine as a thread and...
Página 326 - FIRST LESSONS IN ARITHMETIC. The First Lessons in Arithmetic begin with counting, and advance step by step through all the simple combinations of numbers. In order that the pupil may be impressed with the fact that numbers express a collection of units, or things of the same kind, the unit, in the beginning, is represented by a star, and the child should be made to count the stars in all cases where they are used. Having once fixed in the...
Página 326 - Each idea is first presented to the mind either by an example or an illustration, and then the principle, or abstract idea, is stated in general terms. Great care has been taken to attain simplicity and accuracy in the definitions and rules, and at the same time so to frame them as to make them introductory to the higher branches of mathematical science. No definition or rule is given until the mind of the pupil has been brought to it by a series of simple inductions, so that mental training may...
Página 219 - From the northernmost point of the Gulf of Trieste, where the Isonzo enters, down to the south of Ravenna, there is an uninterrupted series of recent accessions of land, more than one hundred miles in length, which, within the last two thousand years, have increased from two to twenty miles in breadth.
Página 332 - ... means of the simple question and the appropriate answer, a general view of the laws of the physical universe has been rendered so intelligible, as to be easily understood by children who are able to read intelligibly.
Página 240 - The growth of coral appears to cease when the worm is no longer exposed to the washing of the sea. Thus a reef rises in the form of a cauliflower, till its top has gained the level of the highest tides, above which the worm has no power to advance, and the reef of course no longer extends itself upwards. The...