48 jYoiice of Ilaydeiiii Geological Kssays. 



transition, and the secondary, occupy a rank far more ex- 

 tensive and distinguished, than the volcanic and the alluviaL 

 The latter has heen, for years, growing in importance in 

 the view of geologists, and has, in consequence of much 

 contemplation and research, assumed, in Mr. Hayden's 

 eyes, a rank not inferior — to say no more — to that which 

 he allows to the other formations. Indeed his book, (pro- 

 vided that no very commanding importance were attach- 

 ed to the peculiar theory which the author so zealously es- 

 pouses and defends,) might, we imagine, be ver}^ properly, 

 entitled, materials towards a history of the alluvial forma- 

 tions of our globe. In this view, the collection is rich and 

 various, and we are disposed to think with an intelligent 

 scientific friend, must " become a text book, for geologists, 

 in the subjects of which it treats." 



Indeed we are not aware that there can be found, in any 

 single author, so complete a view of alluvial districts, as Mr. 

 Hayden has presented, and it is probable that the elaborate 

 defence of his peculiar theory, has thus, incidentally secu- 

 red to his work, a perpetuity which even that theory, hovv- 

 ever beautiful, might not have enjoyed. 



We do not however mean to prejudge this theory, but per- 

 haps it would have been as well to have made it a deduc- 

 tion from the facts, rather than to have prefixed it to them : 

 the latter method is the most grateful to the majority of 

 minds, while the former is perhaps safer, and more apt to 

 lead us to truth. 



The quotation from Patrin, which Mr. Hayden has intro- 

 duced upon his title page, gives, it is true, a very just view 

 of the uses and consequently vindicability of hypotheses, 

 and certainly the course pursued by our author, is entirely 

 justifiable. 



In his preface he states that '• the principal and only mo- 

 tive by which he has been actuated, is the wish to interest 

 and invite the attention of geologists, naturalists, and scien- 

 tific men of every denomination, to the great and important 

 physical changes, that appear to have taken place upon and 

 near the surface of the earth, in various parts of the world, 

 and more particularly in our own country ; and also to the 

 numerous and interesting facts, that seem to have, not only 

 a direct relation to, but an intimate connexion with those 

 changes: and this with the view of enabhng us to form, 



