yune II, 1874] 



NATURE 



lOI 



place in the list of writers by whom modern geology has 

 been mainly influenced. Indeed the great merits of that 

 far-seeing man are not properly understood and acknov.-- 

 ledged even in his own country ; they are almost un- 

 known among ourselves. At the same time it is a great 

 mistake to attribute to him, as M. Dolfuss does, the 

 founding of the school whose leading principle is " the 

 present the key to the past." Again Lyell's Principles are 

 spoken of as having appeared in the same year (1827) 

 with Prevost's early speculations. But the first volume 

 of the first edition of Lyell's work was not published until 

 1830. While acknowledging the value of the English 

 Ideologist's writings, M. Dolfuss passes a rather severe, 

 and we think not wholly justifiable, criticism upon their 

 style, going even so far as to say that it needs real courage 

 to follow the author of the " Prir.cip'es of Geology " 

 through his weary digressions and diffuse detail of facts. 

 In short, M. Dolfuss looks at the historical development of 

 geological thought through a French pair of spectacles. 

 And in his account of the present condition of geology, 

 the doings of his friends in France bulk as largely as 

 those of all the rest of the world put together. This is a 

 very innocent vanity, especially as it is coupled with 

 profound respect for, though inadequate knowledge of, the 

 " opinions contemporaincs a I'etranger." But it evidently 

 deprives its author's summary of the weight which a broad 

 and impartial review would have had. 



As regards M. Dolfuss's facts, he certainly does not 

 trouble us with any measure of that wearisome detail 

 which he deplores in some English writers. Indeed, 

 his references to the geological formations are so 

 sketch)', that great portions of them might have been 

 as well omitted. Greater development might have 

 then been given to those whence the author can cite 

 the largest body of evidence in favour of his views. 

 It would have been still better, however, had he 

 been aware of the researches made in other countries, 

 notably in Britain, regarding the physical geography of 

 former geological periods. He could then have filled up 

 a good many blanks in his narrative, particularly as 

 regards the older formations. He dwells on the artifi- 

 ciality of the subdivisions of the geological record, the 

 necessity for constantly judging of their value by reference 

 to analogous cases in operation at the present time, the 

 value of a species in stratigraphy and in palaeontology. 

 Much of what he has to say on these subjects has long 

 been familiar to working geologists in this country, and 

 they will be pleased to see these sound notions gaining 

 ground abroad, and displacing the systematic " cut and 

 dry" measuring-rod style of subdivision and classification 

 which looks so pretty in the pages of D'Orbigny, but 

 which has no counterpart in nature. As a curious illus- 

 tration of the want of wide reading we may notice that 

 while discussing the nature and value of species as land- 

 marks in the geological record the author seems unaware 

 of Ramsay's important observations on "breaks in suc- 

 cession" among organic remains. We earnestly re- 

 commend him not to confine his studies to such foreign 

 memoirs as may chance to find themselves honoured by 

 translation into the Revue des Corns Scientifiques, 

 but to seek out the original sources and learn what a vast 

 amount of sound geological work bearing on the subject 

 he has at heart lias been accomplished in recent years 



outside of France, in which French geologists have taken 

 no share, and of which it is to be suspected they remain 

 to a large extent in wilful and perhaps happy ignorance. 



Prof. Contjean's " Elements de G&logie " is a 

 singularly excellent work; in scope it travels over a 

 vast range of subjects— astronomy, physical geography, 

 meteorology, mineralogy, and other branches of Sci- 

 ence, besides the two which specially appear on the 

 title-page. So far as we have examined it, the book is 

 careful, exact, and full. Prof. Contjean takes his readers 

 first through planetary space, and having given them 

 some notion of what it is he brings them down to Mother 

 Earth, and proceeds to dissect her with great cleverness. 

 At the outset he states the phenomena connected with the 

 position of our globe as a planet, and then leads us 

 through the physical characters of the surrounding at- 

 mosphere, the seas, and the solid crust, with its overlying 

 plains, valleys, and mountains. Having in this way de- 

 scribed the parts of the earth he proceeds to give a most 

 clear and satisfactory account of the phenomena of which 

 the earth is at present the theatre — those of the air, of 

 water, whether solid, as snow and ice, or liquid, as rain 

 streams, and lakes ; of the solid land, such as earthquakes 

 and volcanoes ; and, lastly, of the organic influences at 

 work in producing changes on the earth's surface. On 

 this solid foundation of knowledge as to what our globe 

 is at the present time the author in the last part of his 

 book builds his narrative of what that globe has been in 

 past ages. He now gives a succinct and rather meagre 

 account of rocks and minerals, followed up by a much 

 better disquisition on sedimentation (a word, by the way 

 which we might advantageously introduce into our Eng- 

 lish geological vocabulary). His paragraphs devoted to 

 geological structure — faults, joints, cleavage, cSic— -furnish 

 a fresh example of how little the value of these parts of 

 practical geology is understood abroad. What we ordi- 

 narily term stratigraphical or historical geology, that is 

 the history of the various geological formations, occupies 

 relatively but a small p^rt of the book. It ought to have 

 been fuller. The various formations for the sake of con- 

 venience might have been more sharply and clearly dis- 

 tinguished from each other in the printing. Above all in- 

 formation should have been given regarding the nature, suc- 

 cession, and geographical distribution of the several rocks 

 or formations from which the story of the geological record 

 is compiled. The pala;ontological ihiimc under each 

 formation is good as far as it goes, and is well illustrated 

 with good figures. Throughout the volume the illustra- 

 tions are much above the average and have likewise the 

 great redeeming feature of not being merely repetitions 

 of the same old drawings which have done duty in text- 

 books in almost every language under the sun for the last 

 twenty or thirty years. 



Prof. Contjean has produced a book which is likely to 

 be in the highest degree useful to his countrymen. He 

 not only gives a clc.r and intelligible digest of what is 

 known regarding the several subjects on which he treats, 

 but intersperses heie and there original discussions of his 

 own, which are full of interest, and give us a very favour- 

 able impression of his powers, both as a thinker and 

 writer. We would especially cite his examination of M. 

 Elie de Beaumont's theory of the elevation of mountain 

 chains. In this country, where the theory of that distin- 



