DE LA RICHE'S GEOLOGICAL REPORT—MURCIIISON'S SILURIAN SYSTEM.
HOWEVER important to the scientific geologist, or valuable to men whose estates are seated in the West of England, and who way feel disposed to ransack the bowels of the earth after mineral treasures, the matter of both these works is of too scientific, not to say of too minute and technical a kind, to be available for our columns at any length. Leaving, then, their more recondite matter to periodicals devoted to such subjects, we will just indicate the scope and cha- racter of each work. Mr. DE LA IINcun is Director of the Ordnance Geological Sur- vey ; and his volume, published by the Lords of the Treasury at the public expense, is a Report compiled from his own labours, and the materials furnished by the persons employed on the undertaking. The district surveyed consists of Cornwall, Devonshire, and West Somerset ; and, besides a sketch of the physical features of each county and an appendix of curious matters relating to the Cornish mines, the Report embraccs—l. A descriptive survey of the strata of the districts ; which for the most part would be all but unintelli- gible to the general reader, as the numerous geological terms, so pregnant with meaning to the skilful, convey no ideas whatever to uninitiated minds. 2. An account of the mineral veins and " faults," with theoretical observations on their formation and filling-in; to which the preceding observation applies, though not to the same extent. 3. Remarks on superficial detritus and " stream tin," (that is, pebbles containing tin, and distributed by the action of water,) and on submarine forests and raised estuaries and beaches; which are of a more general character, but still requiring geological learning to follow freely. 4. A view of the action of the sea on the coast, and the effects of atmospheric influence, as in decom- P°sin°. rocks, is more curious, and generally suggestive: who knows, after all, but that some of the Druidical remains may be found to be the work of time, and merely fashioned by the Druids. 5. A chapter of considerable interest on economic geology ; embrac- lug agriculture, materials for roads and buildings, as well as mineral springs, harbours, and mines. To relish the whole of this section, will indeed require some knowledge of the subject ; but in- dependent of this taste, there are many parts of practical use or of popular interest. Of the latter kind we will take a specimen, not merely on its own account, but because it is the most specific and authoritative reply that we have yet seen to an often-disputed as- sertion of ADAM SMITH, that the agricultural labourer is the most intelligent of the working classes.
ErrEcrs 01' GEOLOGY ON MANUFACTURES AND MAN.
" Perhaps there are few localities in which the advantages of geographical situation, combined with cheap fuel, arising from geological position, arc better exemplified than at Swansea, where not only the copper Ores of Cornwall and Ireland, but those also of Cuba and Chili, are brought to be smelted; these ad- vantages even rendering it profitable to transport ores from the western shores of South America round Cape Horn to the fossil vegetation entombed in South Wales. It is not improbable that at some future period the South American copper ores may be reduced to metal more profitably in other and nearer COID1- tries in which sufficient coal may be discovered ; but should this change take place, it would still be due to geological conditions. Merthyr Tydfil, in Gla- morganshire, may be cited as an excellent example of the economic value of geological conditions ; the proximity of the carboniferous limestone, the coal, and ironstone, to each other, in that part of the country, producing a cheap combination of flux, fuel, and ore, scarcely to be surpassed.
" It will readily be understood that, where a considerable- portion of any given population, all other things being equal, lives by labour requiring constant skill, ingenuity, and judgment, that habits of reasoning and thought will be produced which would render it mentally superior to another given population in which the greater number of persons merely followed sore routine occupa- tion during their whole lives, in doing which they were not called upon to exercise any of the mental powers they might happen to possess. Tu those whose pursuits take them among the labouring part of the population, the va- riation in the mental condition of the people in the district under consideration is remarkably striking, This variation is no doubt due to many local causes; hut among them the geological structure of the country would appear to hold a more important place than might, perhaps, at first sight be anticipated. The chief contrast would probably be found between the labourers on the poor loads of the carbonaceous series of North-western Devon and the millers of Cornwall, both considered in the mass. While the tinnier are thinly distri- buted over the country, full of prejudices against improvement, and still often firm believers in witchcraft, ghosts, &c. the miners are thickly congregated to- gether in the neighbourhood of the working lodes, abound with intelligence, and filen the constant exercise of their judgment, upon which indeed the living of a large proportion entirely depends, able to take correct and enlarged views of many other fethjeers thSe these ierdlrtil:lt4 eneileetSei •,:th tlitAr orJtinfity occupations. The miners, nevertheless, in Cornwall and Devon, labour under considerable disadvantages as regards education, when compared with those of many other counties, where milling colleges, or schools, are fonnded. There is not a single place in the whole district where they Call learn the results of the mining experience of other countries, and by combining it with their own advance both their knowledge and its practical application. Neither is there any school to teach them those sciences that bear upon their labours, and which would he so useful to them. The necessity of studying the varying con- ditions of their lodes has, nevertheless, so accustomed their minds to the habit of reasoning, that they certainly, as a mass, greatly exceed in intelligence the other labouring population of the district, which, with the exception of the fishermen and sailors, is chiefly agricultural ; the manufactures carried on in the towns, omitting Tiverton amt Chard, not being sufficiently important to impress a manufacturing character on them."
Of the externals of the Report we may say, that it forms a hand- some octavo of more than 600 pages of letterpress ; and that it is illustrated by a geological map, and eleven plates of sections, be- sides a variety of wood-cuts interspersed through the pages.
The Silurian System of Mr. MURCIIISON is the product of indivi- dual industry, energy, and munificence, carried on for a series of years. Its main purpose is an important one—to show that organic remains arc found in strata where they were formerly assumed not to exist ; and its secondary use is to assist in endeavouring to settle the comparative chronology of various strata. Besides these addi- tions to the principles of geology, Mr. MuniC1nSON, in the means used to reach them, has made a large contribution to the flirts of the science, by a minute survey of an extensive and singular dis- trict, comprising the territory once inhabited by the ancient Silures. The term " Silurian System" is taken from the district described; and has been chosen, after much consideration and discussion, as characteristic of the facts of the work, without pledging any one to any theory or principle to be deduced from them. At the same time, though it has the advantage of safety, it resembles one class of safe men, and is not over explicit. No one from the title could form a notion of the subject of the book. The contents of the work consist of a series of descriptive sur- wys, done with clearness, order, and minuteness, and involving a physical and fossil history of the Silurian region ; but incapable of being exhibited in our columns otherwise than by a brief account. The various systems or genera of strata are first generally de- scribed,—as the trap rocks, oolitic, new red, and carboniferous systems. The geological structure of the different counties in- cluded in the district are next put forth ; these are followed by the superficial deposits,—meaning those formations whose present composition has not been produced by the action of fire, or, in a certain sense, of water ; and the part is concluded by a sketch of
changes during the sera of man's occupation of the earth,—as the formation and drainage of lakes, and the growth of deltas. Having thus given a description of all rocks of an igneous or aqueous origin, an account of their various dislocations, and a view of their superincumbent matter and soils, Mr. Mt:Benison pro- ceeds to present the organic remains, which he has discovered in his laborious survey ; M. AGASS1Z describing the fishes, M. J. DE C. SOWERBY the mollusca and conchifers, Mr. LONSDALE the corals, and the author himself taking the crustaceans. The work is splendidly got up—the size quarto, the paper ex- cellent, the margins ample ; and this bibliographical splendour is accompanied by maps, plates, and illustrations of corresponding quality. But how far so much munificence of appearance was prudent in a book whose circulation is of necessity limited by its subject, may be matter of question. Devoutly do we hope that the " Vice-President of the Geological Society of London" may cover his outlay ; we imagine he never expected to be re- munerated for his labour.
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