March 22, 1888] 



NATURE 



483 



and floras of the Palaeozoic, the Mesozoic, and the Kaino- 

 zoic divisions respectively. In these reviews of the great 

 geological epochs, the distinctive features of their life- 

 history are ably summarized ; and the subject is made 

 clearer by the insertion of sixteen lithographic plates, 

 the fossils represented upon these being very judiciously 

 selected and admirably drawn. 



Most readers will look with much interest to the later 

 chapters, in which the author deals with the Tertiary and 

 post-Tertiary deposits, the study of which has been so 

 greatly advanced by the author's own researches. Prof. 

 Prestwich has in several very important points modi- 

 fied some of the conclusions of his classic papers upon 

 these questions. He now accepts, with most modern 

 geologists, the term " Oligocene " as usefully embracing 

 the strata known as the " Fluvio-marine strata" of the 

 Hampshire Basin, and separates them from the Eocene 

 proper. He also points out for the first time the close 

 connection of the so called " Lower Bagshot Sands " with 

 the London Clay, placing them in the Lower Eocene ; while 

 the Middle and Upper Bagshof s of the London Basin, and 

 the Bracklesham and Barton series of the Hampshire 

 Basin, constitute his Upper Eocene. This view has recently 

 been explained and defended in a paper which the author 

 has read before the Geological Society, and is one which 

 we think will meet with very general acceptance. In 

 his account of the post-Pliocene (or, as he prefers to call 

 them, the Quaternary or Pleistocene) deposits, it will also 

 be seen that Prof. Prestwich has so far departed from his 

 earlier published views as to admit the probability of some 

 of the deposits which contain relics of human handiwork 

 belonging to a period when glacial conditions prevailed in 

 this country. 



The work concludes with three chapters of a theoretical 

 character. In the first of these Prof. Prestwich argues 

 against the acceptance of any views, like those of Dr. 

 Croll, which would define the exact date of the Glacial 

 period by reference to astronomical events. Accepting 

 the probability that man may have lived at the period 

 of the greatest glaciation, the author boldly proceeds to 

 challenge the comrrion opinion that this period of glaciation 

 must have been separated by an enormous interval of time 

 from the present day. He even suggests that the Glacial 

 period may not have had a duration of more than from 

 15,000 to 25,000 years, and the post-Glacial period he 

 thinks may be restricted to 10,000 or 15,000 years ! 



The facts which seem to have had the greatest weight 

 in leading Prof. Prestwich to these, at first sight, startling 

 conclusions, are those connected with the movements of 

 the great ice-sheets in Greenland. The recent observations 

 of Rink and Helland seem to show that the data afforded 

 by the diminutive Alpine glaciers are utterly inapplicable 

 to the vast masses of ice which must have flowed over 

 extensive areas during the Glacial period. While the 

 Alpine glaciers progress at an average rate of a foot per 

 day, the great Greenland ice-sheet advances 35 feet per day, 

 and the efi'ects produced in a given time by such rapidly 

 moving masses must be proportionately great. There will 

 doubtless be much difference of opinion among geologists 

 upon the important suggestions made by Prof. Prestwich ; 

 but in any future discussions of the subject it must be 

 admitted by everyone that the data upon which all our 

 reasoning has to be based has been profoundly modifi.ed 



by the remarkable observations made by the Danish 

 Scientific Commission upon the inland ice of Greenland. 



In his penultimate chapter, the author points out the 

 grounds for the view — of which he has long been one of the 

 ablest advocates — that the earth's solid crust is a com- 

 paratively thin one ; and he indicates the lines of argu- 

 ment by which the objections of mathematicians and 

 physicists to such views can best be met. While demurring 

 to the doctrine of the permanence of continental and 

 oceanic areas, he justly points to the great effects which 

 must result from the flow of ice-cold water over the bottom 

 of the great oceanic depressions. 



The last chapter, on " The Primitive State of the Earth," 

 is an attempt to link the geological history on to that ar- 

 rived at by the studies of the astronomer. Due importance 

 is justly attached to the evidence aff"orded by meteorites, 

 and an excellent summary is given of Daubrde's admirable 

 researches. But here, as the author freely admits, he is 

 on less secure ground than in the earlier chapters of his 

 book, and the utmost he aims at doing is to supply a 

 working hypothesis. 



Both Prof. Prestwich and the Delegates of the Oxford 

 University Press are to be congratulated upon the manner 

 in which the work . has been got up. The printing is 

 admirably clear, and the woodcuts, most of which are 

 original, are of exceptional excellence. The plates, which 

 have been very skilfully drawn on stone by Miss Gertrude 

 Woodward, exhibit the characters of the fossils illustrated 

 in a manner superior to what we have ever seen attempted 

 in any geological text-book. The coloured geological map 

 of Europe, which has been prepared under the supervision 

 of Mr. W. Topley, is brought up to date, and is very 

 clear and serviceable. 



To the splendid work now so auspiciously completed 

 at the termination of the author's professorial career 

 at Oxford, we heartily wish all the success it so well 

 deserves. J. W. J. 



VACCINATION. 



Cow-Pox and Vaccinal Syphilis. By C. Creighton. 



(London : Cassell, 1887.) 

 Vaccination Vindicated. By J. C. McVail. (London : 



Cassell, 1887.) 



TWO new books have lately appeared on vaccination ; 

 one on the natural history of" Cow-Pox and Vaccinal 

 Syphilis," by Dr. Charles Creighton ; the other, " Vaccina- 

 tion Vindicated," by Dr. J. C. McVail. 



The first mentioned, that by Dr. Creighton, is a very 

 misleading work. The first four chapters are almost 

 entirely devoted to a wholesale abuse of Jenner, and the 

 fact that Jenner has called the cow-pox the " variolc-e 

 vaccinioe," is especially singled out for more than usual 

 criticism ; but the very virulence of the abuse will lead 

 to its condemnation, and the memory of the man who 

 deserves so well of his country will not therefore be 

 unjustly thought of by his countrymen. 



The whole burden of the rest of the book may be 

 summed up in a passage that occurs on p. 155: "The 

 real affinity of cow-pox is not to the small-pox but to 

 the great-pox." Let it be remembered that these two 

 diseases are placed together by the science of medicine 



