New Edilion hy Prof. E. G. Seeleij. 571 



existing divisions of the strata, since the higher forms are chiefly 

 known from the Lias, the Cambridge Greensand and the London 

 Clay. The Lamellibranchiata furnish many surviving types in the 

 Primary rocks, especially the Carboniferous ; others become knovt^n 

 in the Trias, Lias, Neocomian, Cretaceous, and Lower and Middle 

 Tertiary. The Gasteropoda commence gradually, one or two with 

 a formation, though they are most numerous in the Carboniferous, 

 Lias, and Chalk, until the Lower Tertiary introduces the majority 

 of living forms. Hence there are nine or ten great palBeontological 

 divisions of British strata. 



" Paleeontology has often been regarded merely as the aid which a 

 naturalist contributes to the work of the stratigraphical geologist. 

 But in addition to this work, which it was at first called upon to 

 perform, palseontology has a more important role in the future 

 history of science, in demonstrating the steps in the evolution and 

 succession of faunas; and on this basis its evidence must always be 

 important in forming a useful geological classification of strata. It 

 also contributes important evidence of physical changes which took 

 place in adjacent regions. But the physical and palseontological 

 evidences rarely coincide ; so that for some time to come strati- 

 graphical classifications should be made independently, first upon 

 the evidences of the Physical History of a Eegion, and secondly, 

 upon its Succession of Life. The two methods may eventually be 

 united, but it can only be by discovering the physical conditions 

 which limited, determined, and changed the mineral characters of 

 the strata, and changed the distribution of fauna and flora in the 

 area which the strata occupy." 



It is diflBcult in the limited space at our command to do fitting 

 justice to so large a work. The PalEeontological chapters, although 

 not more than one-fifth of the book, are i-eplete with interest. (Some 

 printer's errors need correction on p. 491, but these will doubtless 

 be eliminated in the later copies.) It is satisfactory to know from 

 Prof. Seeley that he has preserved every page of the original work 

 that was in any way valuable. And also that notwithstanding the 

 large additions and revisions, the spirit of the old book has been 

 preserved, and that it has been revivified with the spirit of the 

 newer geology which is unfolding. 



In these days of good books of all kinds, we are no longer at 

 a loss to find a text-book upon a particular subject, but the serious 

 question is rather which shall one choose ? It is most satisfactory 

 to be able to say that Professor H. G. Seeley has maintained in his 

 Physical Geology and Palaeontology the high reputation he already 

 deservedly bears as a teacher, and that it reflects credit on the name 

 of Phillips with which the work is associated. We shall look 

 anxiously for the appearance of Mr. Etheridge's New Year's Volume, 

 — On Stratigraphical Geology and Palaeontology, — which is to form 

 Part II. of the present work. 



