246 Correspondence — Mr, John Young, 



prior to the deposition of any of the gravel or ' loess' now to be seen 

 there"), he floods the valley " eighty feet above the present level of 

 the Somme." These prodigious bodies of water do not in the least 

 erode the soft chalk sides, or the bed of the valley, but, on the con- 

 trary, they deposit the gravel terraces as their high-water mark. 

 Flints, therefore, in the pluvial period must have been lighter than 

 water, and must have floated on the surface to their present posi- 

 tion. In periods other than the pluvial one drift is driven along 

 the beds of rivers and valleys. And these terraces of the Somme 

 have been the beds of the river or valley, as I have had the honour 

 to state in the Geological Magazine for May, 1867. 



Brook WOOD Park, Alresford. George Greenwood, Colonel. 



CYCLOPHYLLUM FUNGITES. 



Sir, — In the last number of the Geological Magazine, Dr. 

 Duncan made some remarks upon a statement of mine which 

 appeared in your Magazine for March, 1868. I beg now to offer a 

 few words of explanation. 



Dr. Duncan writes, " Mr. Young also appears to have stated that 

 David Ure was the original discoverer of the genus in question, and 

 that Prof. M'Coy had clearly delineated the various jDarts consti- 

 tuting the internal organization of this coral ; to these statements I 

 must give my unqualified contradiction." 



In my remarks I only wished to imply that David Ure was the 

 original discoverer of the species of coral upon which Dr. Duncan's 

 new genus was founded, not the discoverer or author of the various 

 generic and specific names that have since been applied to it. 



As to whether Prof. M'Coy has or has not delineated in his 

 figures and description all the essential points in the internal organi- 

 zation of this coral, or whether Dr. Duncan is warranted in estab- 

 lishing new generic characters upon the points which he says he 

 was the first to discover, this I will leave to the decision of those 

 palseontologists who are better able than I am to decide in this 

 matter. The parts of this coral upon which Dr. Duncan founds his 

 generic distinctions, were not, I think, so entirely unknown to Prof. 

 M'Coy, as Dr. Duncan's remarks would imply. With him, how- 

 ever, they did not constitute points of generic distinction, but only 

 served, as he states, to characterise a well-marked species. 



I was induced to make those remarks to which Dr. Duncan has 

 seen fit to repl}^, from being present at a meeting of the Geological 

 Society of Glasgow, on the 18th of April, 1867, when Mr. James 

 Thomson exhibited a coral, which he asserted to be new to science 

 (I will not say that he did this with Dr. Duncan's consent). I had 

 not then seen Messrs. Duncan and Thomson's joint-paper on Cyclo- 

 phjllum fimgites, but I stated in my remarks that I believed it was 

 founded upon the species of coral first discovered by David Ure, 

 and figured by him in his book as a Fungites in the year 1793, but 

 which had subsequently received new generic and specific names 

 from Fleming, M'Coy, and Milne-Edwards. 



