ACCOUNT OF BOOKS. 



939 



*< The importance of this ques- 

 tion will be fully perceived, if it 

 be considered that we cannot ob- 

 tain any informaiion respecting the 

 history of our globe, but from the 

 continents themselves ; since from 

 the sea we can learn nothing, ex- 

 cept by the relations which it bears 

 to them. But even the continents 

 could afford us no instruction, 

 were it not at present admitted by 

 the most distinguished geologists, 

 among whom I place Dr. Hutton 

 and Mr. Playfair, that their birth 

 is to be ascribed to some revolu- 

 tion on the globe, and not to any 

 successive and slow cause, as had 

 been supposed in several systems, 

 before observations had been car- 

 ried to their present extent. Ifjthen, 

 it can be determined with certain- 

 ty, what the state of the continents 

 was at the time of their first pro- 

 duction ; that is to say, if, amcng 

 the phenomena which their surface 

 exhibits, we can distinguish those 

 which originally belonged to them, 

 the epoch of their birth becomes a 

 point, which divides the history of 

 the earth, by well-known monu- 

 ments, into two very distinct pe- 

 riods, one prior, the other poste- 

 rior, to that epoch ; and through- 

 out the whole course of this his- 

 tory, these monuments will be- 

 come our faithful guides. Having 

 fully developed this subject in my 

 former work, my present purpose 

 is to point out in what manner ob- 

 servation must be directed, in or- 

 der to discover these monuments, 

 amidst the variety of phenomena 

 belonging to the surface of the 

 earth. 



<* Since the whole mass of our 

 continents consists of what are 

 called mineral strata, the origin of 



these is undoubtedly a geological 

 point, which it is very important 

 to determine ; and here I may 

 again set out from a proposition, 

 agreed to by all those who have 

 sutficiently studied them ; namely, 

 that they have been successively 

 formed, one above another, on the 

 bottom of the sea, in a situation 

 nearly horizontal and continuous; 

 and that all the fractures and dis- 

 locations observed in them are the 

 effects af catastrophes subsequent 

 to their formation. On this par- 

 ticular, my opinion is the same as 

 that of Mr. Playfair; excepting 

 when, with Dr. Hutton, he ex- 

 cludes, from the rank of mineral 

 strata, granite and other con- 

 temporary substances, considering 

 them as products of fusion, poste- 

 rior to those to which he reserves 

 the name of strata. But, for the 

 present, I lay aside this object, as 

 not essential ; and I shall intro- 

 duce it only when, in the course of 

 my travels, 1 shall come to places 

 where we have both made observa- 

 tions on granite. 



" Considering here, then, only 

 the strata of which the successive 

 formation at the bottom of the sea 

 is not questioned, it is certain that 

 these strata, and their catastrophes, 

 are the only archives in which we 

 may read the history of the earth, 

 previously to the birth of our pre- 

 sent continents. Now the most 

 striking features of the latter are, 

 with respect to their surface, 

 mountains, and valleys, hills and 

 vales, and the sinuosities of plains; 

 and, with respect to their outline, 

 capes, gulphs, and bays, and the 

 steep cliffs on some of their coasts; 

 we must therefore examine whe- 

 ther these features originally be- 

 longed 



