466 



NATURE 



[April II, 1872 I 



LYELL'S PRINCIPLES OF GEOLOGY 



'T*HE appearance of a new edition of the " Principles 

 •'■ of Geology " would mark a fitting time to pass in re- 

 view the state of Geologic Science, to count up what has 

 been added to the treasury of truth, and inquire in what 

 direction and by what methods the pioneers of Science 

 encourage us to search for new facts. Within the limits 

 of a short review, however, it is impossible to do more 

 tlian call attention to a few of the more striking points 

 which seem to illustrate the principles which we should 

 apply to the examination of the phenomena of the crust of 

 the earth. 



We have before us the first edition of the " Principles 

 of Geology," published in 1830, and that just issued in 

 1S72. It is a remarkable fact that any work on a science 

 which has made such rapid progress as Geology has 

 within the last forty-two years, should, while maintaining 

 the foremost place, have remained so little altered during 

 that period. Almost all the passages which lay down the 

 principles remain word for word as they were originally 

 given to the world ; the changes made from time to time 

 bemg chiefly in the introduction of better illustrations or 



the consideration of new questions which the progress of 



research has raised ; but to all we find the same methods 

 applied, and from all the same conclusions drawn as to 

 the operation of nature in the production of the visible 

 crust of the earth. 



What, then, are the principles laid down ? Thoroughly 

 to understand this, we ought to follow our author through 

 the interesting outline he gives of the progress of geolo- 

 gical inquiry, in order to realise fully the opinions which 

 prevailed when he first entered the arena. But we will 

 only refer to the views of Hutton, which most nearly ap- 

 proach those of Sir Charles Lyell, who points out that 

 " the characteristic feature of the Huttonian theory was 

 the exclusion of all causes not supposed to belong to the 

 present order of nature. . . . But Hutton had made 

 no step beyond Hooke, Moro, and Raspe, in pointing out 

 in what manner the laws now governing subterranean 

 movements might bring about geological changes if suffi- 

 cient time be allowed. He therefore required alternate 

 periods of general disturbance and repose ; and such he 

 believed had been and would for ever be the course of 

 nature" (ist ed. p. 63, nth ed. p. 76). 



The views which Hutton and his eloquent illustrator 



-•s TowEK (Zuercli-Tuugm) near Viiiscii i^ THE Cant. 

 (From a S/ic-tJl iy Lady Lyell, taken ScJ'Umbcr iSj?) 



Playfair taught were far from meeting with general recep- 

 tion, and Lyell had to combat the catastrophic views of 

 their opponents, and also to carry Hutton's uniformitarian 

 principle further than Hutton himself allowed, and show 

 by an appeal to observations in regions which arc and 

 have recently been in a state of volcanic activity that 

 local catastrophic action is not inconsistent with con- 

 tinuity of causation. " There can be no doubt," says Sir 

 Charles, "that periods of disturbance and repose have 

 followed each other in succession in every region of the 

 globe, but it may be equally true that the energy of sub- 

 terranean movements has been always uniform as regards 

 the whole earth. The force of earthquakes may for a cycle 

 of years have been invariably confined as it is now, to 

 large but determinate spaces, and may then have gradually 

 shifted its position, so that another region which had for 

 ages been at rest became in its turn the great theatre of 

 action " (ist ed. p. 64, nth ed. p. 77). 



Our author places before us a vast array of facts 

 collected by himself and others all over the world, which 



_ * " The Principles of Geology, or the Modern Changes of the Earth and 

 its Inhabitants considered as illustrations of Geology." By Sir Charles 

 Lyell, Bart,_ nth and entirely revised edition. (London: J. Murray, 1872.) 



show the ceaseless waste going on by rain, ri\ers, sea, 

 frost, and ice. 



The hills are shadow?, and they flow 

 From form to form, and nothing stands. 

 He explains how all the land must in time be carried 

 away and one vast ocean roll all round the world were 

 there no compensating forces. But then he points out to 

 us that nature does provide a compensating action in the 

 accumulation of volcanic ash and lava thrown out 

 during eruptions, in the upheaval of large tracts of land 

 from below the sea, and still further, that it is part of 

 nature's plan to shift the scene of action. 



We will select a few examples from the facts addu;ed 

 in proof of the gradual waste of the land. 



Speaking of the effect produced by rain, our author 

 says :— " It is not often that the effects of the denuding 

 action of rain can be studied separately or as distinct 

 from those of running water. There are, however, several 

 cases in the Alps . . . where columns of indurated 

 mud varying in height from 20ft. to looft , and usually 

 capped by a single stone, have been separated by rain 

 from the terrace of which they once formed a part, and 



