i873-j Notices of Books. 525 



Lightning during the summers of 1868, '69, and '70, and show 

 him how vast are the conquests that may yet be made in the 

 new and higher career of honour which is opened up for the 

 British flag by such expeditions. 



Most of our readers know already, by the reports' that have 

 been published from time to time -in the scientific and other 

 journals, what was done during these well-spent summers ; and 

 we recommend all to revel, as we have done, in the luxury of 

 travelling again over Dr. Thompson's connected and beautifully 

 illustrated narrative of the whole of the proceedings. As a pro- 

 foundly valuable contribution to science, as a literary effort of 

 high order, and as an elegantly artistic volume, this book is 

 worthy of the warmest praise. It is indeed fortunate that the 

 results of such important expeditions should be recorded byso 

 able a writer as Dr. Thompson, and that such a writer should 

 find such spirited publishers as Messrs. Macmillan and Co. 



The simplicity of style and clearness of description are very 

 high merits. The whole book is readable by any man or woman 

 of ordinary liberal education, and this great merit is attained 

 without any sacrifice of scientific technicality or precision. 

 We sincerely hope that the privilege of reading the original 

 record of such important scientific work will be fully and popu- 

 larly appreciated, as it is not often that researches which have 

 had so important an influence on some of the foundations of 

 cosmical science are thus easily accessible. 



The most important philosophical results of the expeditions 

 are summed up in the concluding essay on the " Continuity of 

 the Chalk," wherein the author states his reasons for concluding 

 that, in spite of the myriads or millions of centuries that must 

 have elapsed since the deposit of the chalk which lies beneath 

 our feet here in London, there has been no chasm of time, no 

 interregnum of deposit between this ancient and the actual but 

 somewhat modified chalk formation now proceeding at the bottom 

 of the Atlantic. 



Admitting to a certain extent the justice of the objections 

 made by Sir Roderick Murchison and Sir Charles Lyell, to his 

 early expression that "we are still living in the cretaceous 

 epoch," on account of the indefinite sense of the terms "geolo- 

 gical epoch" and "geological period," Dr. Thompson shows 

 good reason for maintaining the conclusion which these words 

 were intended to express, viz., that " the various groups of 

 fossils characterising the tertiary beds of Europe and North 

 America represent the constantly altering fauna of the shallower 

 portion of an ocean whose depths are still occupied by a deposit 

 which has been accumulating continuously from the period of 

 the pre-tertiary chalk, and which perpetuates with much modifi- 

 cation the pre-tertiary chalk fauna;" or otherwise, that "we 

 must regard the tertiaries as the deposits formed and exposed by 

 depressions and upheavals of the cretaceous sea : of a sea 



VOL. III. (n.S.) 3 Y 



