114 The Irish Naturalist. Oct., 



costulata. For other examples of current-borne species 

 see the Report, British Association, Leeds, 1890, page 



415- 



It is probably due to current action that so many shells 



of southern origin have found their way into the deeps off 



S.W. Ireland, where Cassidaria rugosa, Randla gigantea, 



and even Pedicularia sicula are found living with others of 



purely northern type like Voliimitra groenlandica. 



The term " boulder-clav " as commonlv used is not 

 alwavs appropriate, and I agree with Dr. Crosskey that it 

 should be confined to the inorganic " till " of land-ice origin, 

 and not to the often fossiliferous clays of marine origin, 

 whatever stones they may contain. 



The substance called "boulder-clay" in maritime districts 

 is chiefly the sediment of the turbid streams pouring from 

 the ice-front or face, or water. sorted material carried by 

 floating ice. The late K. Brown^ noticed that such a stream 

 deposited a layer averaging three inches per annum over a 

 sea-bottom full of marine organisms and various stones, 

 and remarks that such a deposit was indistinguishable from 

 the usual so-called " boulder-clay." 



A very representative series of the Wexford shells has 

 been forwarded to the National Museum, Dublin, and 

 nearly 100 examples of the Wexford-Manx mollusca have 

 been already figured by Mr. F. W. Harmer, m.a., f.g.s. in 

 his "Monograph of the Pliocene Mollusca" (Palaeontographi- 

 cal Society) of which the first volume has now been com- 

 pleted. 



Cringleford, Norwich 



^ Brown, R. : On the Physics of Arctic Ice. Quart. Jour. Geo'. Soc , 

 xxvi , 1870, pp. 671-701. 



