ANNIVERSARY ADDRESS OF THE PRESIDENT. xlv 



donts ; and alluding to the difficulty he had experienced with respect 

 to its heterocercal tail, the Professor remarks that he now expects to 

 find that character in fishes of various families detected amid the 

 oldest accumulations as well as in the youngest embryo state of our 

 actual fishes. Sir Philip Egerton has satisfied himself that *' the 

 generic characters of Platysomus are in close affinity with those of 

 Gyrodus and Microdon, but that it differs from these and all other 

 known Pycnodonts in having a heterocerque tail." It is gratifying 

 thus to see two cultivators of the same branch of science working so 

 completely in harmony, and conferring with each other so amicably 

 on points of difference ; so that instead of conclusions being hostilely 

 retained which may no longer be tenable, — and the progress of all 

 branches of science shows us how first-impressions have to be modi- 

 fied, — truth becomes the only object, no matter by whom it may be 

 brought to light. 



To Mr. Morris we are indebted for a communication on Neritoma, 

 a fossil genus of gasteropodous molluscs allied to Nerita. He shows 

 that the shells in question, though allied to Nerita, are yet aberrant 

 from it, and that they become interesting from connecting the true 

 Nerites with Amphibola, and as adding another instance of certain 

 genera of molluscs with analogous forms presenting the similar cha- 

 racter of a greater or less sinus on the outer lip. The fossil whence 

 the generic description is given was from the upper portion of the 

 Portland beds, at Swindon, Wiltshire, and was also interesting as 

 distinctly exhibiting the markings on the surface. 



Though this is the only communication from INIr. Morris during 

 the past year in the form of a single paper, we have to thank our 

 able colleague for his constant readiness to assist the labours of others 

 of our contributors of memoirs whenever they may request him so 

 to do, and for thus adding to our stock of that knowledge which the 

 talents of Mr. Morris so qualify him to advance, and for the further- 

 ance of which we could wish him more leisure than his occupations 

 now present. 



Superposition of Rocks, their supposed equivalents in (liferent re- 

 gions, and general classification. 



In a memoir on the principal geological features of the salt-field 

 of Cheshire and the adjoining districts, Mr. Ormerod has presented 

 us with numerous facts respecting the occurrence of rock-salt and 

 brine-springs in that part of England, the beds in which the salt and 

 brine are found, and the older rocks on which these beds repose. The 

 latter constitute the range of coal-measures running northerly from 

 Cheadle and Newcastle-under-Lyne on the south, towards Man- 

 chester and Stayley Bridge on the north, a small portion of mountain 

 or carboniferous limestone rising in an elongated anticlinal ridge 

 near Congleton. These older rocks are well-known to have been dis- 

 turbed, crumpled and fractured anterior to the deposits commonly 

 known as the New Red Sandstone, the latter resting unconformably 

 upon and entering valleys in the former, many a patch, not yet 

 removed by denudation, showing the covering of these red marls, 



