192 Observations on some Parts ofMr. De la Beche's Paper 



of beds of the newest formation, deposited by causes now in 

 operation, continually going on, such as the tranquil action of 



rivers, &c. ; by " the diluvial," a group formed earlier than the 

 last, ending where it began, the effects of violent and sudden 

 inundations. But will not the latter naturally be somewhat 

 intermingled with, and even preceded by, some of the for- 

 mer ? for the first of the alluvial deposits will manifestly be 

 coincident with the commencement of the present state of 

 our globe (meaning thereby, the effects of the last of the geo- 

 logical i-evolutions, the one immediately preceding the creation 

 of the cavern hyaenas and bears), and will therefore precede, 

 be covered, and perhaps partly destroyed by, the earliest 

 diluvial catastrophe. Where, then, are the limits of this group 

 to be found ? Or, how are we to know the one from the other ? 

 Not surely by the presence of sand, and rolled portions of the 

 older rocks ; for, these we may find among the silty deposits of 

 any considerable river. We must in this case confine the di- 

 luvial group to the gravel and boulders on hill-tops and other 

 situations, not likely to have ever formed part of the beds of 

 water- courses. But can these be classed as a distinct group, 

 formed in all probability at various periods since the com- 

 mencement of the present state of our globe ? Mr. Vernon 

 (Phil. Mag. and Annals, Jan. 1830) has clearly shown the oc- 



' currence of alluvial deposits previous to any signs of diluvial ac- 

 tion having taken place : if therefore we retain the terms, and 

 distinguish, as the latter gentleman does, the diluvial beds by 

 large stones being present, must we not divide the groups into 

 three, — antediluvial alluvia, diluvia, postdiluvial alluvia? Or 

 perhaps a fourth would be necessary, designating a silty deposit 

 lying between two gravel beds, if we should ever meet with 

 such a section as diluvial alluvia. What is to prevent us from 

 removing all this difficulty by classing the groups together, after 

 the manner of Dr. Fleming in his excellent " Tabular View of 

 the Geological Epochs" (Preface to " British Animals"), as a 

 modern group, or by any other name adapted for the purpose ; 

 signifying in detail, the causes of the very different effects 

 portrayed in the two parts ? Again, supposing that the al- 

 luvia constitute a distinct group formed since the diluvial period, 

 as Mr.De la Beche seems to contend, I think, with Mr. Vernon, 

 that Mr. D.has very insufficient data before him, for concluding 

 that man and monkeys first appeared during this epoch. Can a 

 few caverns and gravel-beds, perhaps inadequately searched, in 

 one quarter of the globe, and that not the most likely one to 

 be the burial-place of the human race, render the fact even 

 presumable? As Mr. Vernon remarks, the only consequence 

 that can justly be inferred is, that these regions of the earth 



were 



