xliv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



cies of the same genus do in the present day, namely in rivers and 

 estuaries), borne into seas in which molluscs of the same kinds as 

 have their remains entombed in our cretaceous rocks, were living. 



From the general characters of the other saurians found we should 

 also infer that their habits were not such as to render the sea among 

 their usual haunts, but rather that they lived in rivers and estuaries, 

 occasionally coming on the adjoining lands. When we look at the 

 lithological characters of the beds in which these remains are en- 

 tombed, as well as to the state in which the bones are preserved, it 

 at once becomes evident that they have been carried to the situations 

 at or near which they are now discovered, by being rendered specifi- 

 cally lighter than they now are, or formerly could have been. In 

 fact we seem required to consider that flesh was on the bones when 

 they were borne into the seas, amid the deposits and creatures living 

 at the time, in which they are detected. However difficult it may 

 be to wash crocodilian animals into the adjoining seas from out 

 many of the great rivers of the world where these creatures live in 

 multitudes, more particularly where mangrove swamps abound at 

 their embouchures, this is not the case with the short torrent rivers 

 descending from high lands into the seas surrounding islands, as for 

 instance Jamaica and Haj^ti. During a great flood in the Yellahs 

 river, one which takes its rise in the Blue Mountains of Jamaica, 

 and at whose mouth and in the adjoining mangrove swamps the 

 caimans are common, the body of water was so great as to sweep 

 these crocodilians off to sea, where it may be presumed some 

 perished, to leave their bones, at least such as were not swallowed by 

 the large fish, to be mingled with the remains of marine molluscs 

 now living in those seas. In cases of floods of this kind, the sudden- 

 ness of which can be scarcely appreciated by those who have not 

 witnessed the waters of heavy tropical rains discharged by means of 

 a short steep course from high mountains into the sea, many a river 

 and estuary air-breathing creature gets overpowered and carried off 

 before it can reach the protection of eddies near the banks ; and 

 should there be a heavy sea going at the time, as sometimes happens 

 when a hurricane is accompanied by floods of rain, there is a poor 

 chance of their escape from drowning, however well-fitted for living 

 in rivers and estuaries under ordinary conditions. 



True to his promise to add to our palichthyological information, 

 as given in his first memoir read during the past year. Sir Philip 

 Egerton communicated at our last meeting a paper on the affinities 

 of the genus Platysomus. After adverting to the opinions of differ- 

 ent authors, and especially to that of Agassiz, Sir Philip mentions 

 that Mr. King, of Newcastle, had recently submitted to him a spe- 

 cimen of Platysomus macrurus, from the magnesian limestone of 

 Ferry Hill, revealing its dentition, whence it became evident that 

 this genus was a true Pycnodont. A detailed account of its den- 

 tition is given, and it is stated that the genus Glohulodus must 

 be cancelled. Conferring with his friend Professor Agassiz, Sir 

 Philip Egerton received from him a complete agreement in the view 

 that the genus Platysomus should be included among the Pycno- 



