286 Zoology of the Voyage of the Beagle. 



It has been sometimes classed with the crag, and sometimes 

 distinguished from it under the name of diluvium.' 



But the remarks in my former letter had reference to the 

 views I adopted in my Memoir on Suffolk Geology, in dis- 

 tinction to Mr. Lyell's, as first adopted by him ; and it was 

 not till after that Memoir had been read, that I first saw his 

 expression, 'more uncertain age,' in the edition published af- 

 ter the reading of that paper, and the discussion on the very 

 subject of crag and diluvium, in which both you and myself 

 took part at Bristol, in 1836. How far any opinions held by 

 me, in common with others, may have had any influence on 

 the distinguished author and geologist, whose opinion on the 

 subject of the crag and diluvium I ventured to oppose, I can- 

 not presume to say ; yet it is certain, that he held the views 

 I attributed to him, and that he has now only modified them 

 to a certain extent. As my object in this letter is to set my- 

 self right with your readers, I shall not extend it so as to af- 

 ford any further proof that my position as to the different 

 ages of the Suffolk diluvium and the crag, is a correct one. 

 At a future time I may, perhaps, trouble you with a few illustra- 

 tions from my notes upon the subject. 



Your's faithfully, 



W. B. Clarke. 



Stanley Green, 



April 10th, 1838. 



Editor of the Magazine of Natural History. 



REVIEWS. 



Art. I. The Zoology of the Voyage of H.M.S. Beagle, under the 

 command of Captain Fitzroy, during the years 1832—1836. — 

 Published with the approval of the Lords Commissioners of Her 

 Majesty's Treasury. Edited and superintended by Charles Dar- 

 win, Esq. M.A., F.G.S. C.M.Z.S. Naturalist to the Expedition. 

 Part I. No. 1. — The Fossil Mammalia, by Richard Owen, Esq. 

 Professor of Anatomy aud Physiology in the Royal College of Sur- 

 geons. London: Smith, Elder & Co., Cornhill. 1838. 



It is with much pleasure that we take an early opportunity 

 of noticing the commencement of a work, which, when com- 

 plete, will contain a mass of zoological detail, of no ordinary 

 value and interest ; and perhaps unexampled in amount, con- 

 sidered as the result of single-handed research, undertaken 

 by an individual whose attention is known to have been, dur- 

 ing the same time so successfully directed to other matters of 

 philosophical investigation. The circumstances under which 



