ON THE 'MAMURE' GKAVELS OF WEXrORD. 135 



cliiefly Cambrian and Silurian, many beautifully striated.' This descrip- 

 tion so strongly applies to wbat I have termed an illusory drift that at 

 present I am inclined to consider it a similar accumulation. 



This is a drift, or rather a clay, resulting from the decomposition of the 

 metamorphosed Palaeozoic rocks wherever exposed to atmospheric in- 

 fluences. This is well seen between the Slaney and the Forth Mountain, 

 and in and about Wexford, at Killurin and Macmine Junction, and almost 

 everywhere at the foot of the hills along the railway line, wherever a 

 cutting or excavation has been opened. This clay is full of blocks in 

 various stages of degradation, occasionally covered and coloured by iron- 

 froth. The soft nature of the metamorphosed Cambrian rocks renders 

 their situation of less value in this point of view than if they were lime- 

 stones. 



The fauna contained in the gravels is very interesting ; the only 

 hitherto available lists are those made so many years back by Captain 

 James and Professor Forbes, their usefulness being impaired by the un- 

 certainty as to whether the fossils came from the gravel or the marl. I 

 have therefore given in the following only those which I have obtained 

 directly from the gravels, adding subsequently those of the earlier lists. 



A large proportion of the shells are much abraded fragments, very 

 few of the Pelecypoda being intact, the Gastropods suffering less damage. 



The condition in which the remains occur does not altogether suggest 

 more than a normal amount of violence or far removal, since equally 

 broken fragments are to be seen in any ancient or modern sea-beach, such 

 as the raised beach at Thatcher Island, or on the level stretch of sands at 

 Paignton, both in Torbay. 



Their distribution is rather capricious. Professor Forbes, op. cit., 

 p. 377, speaks of the abundance of Purpura lapillns and the presence of 

 Littorina littorea as especially characteristic of the Wexford shelly gravels 

 containing Fusus contrarius. These are rare in the southern parts of the 

 district, where Venus verrucosa, doubtfully recognised by Professor Forbes 

 as a Wexford fossil, is, on the contrary, not uncommon. 



Many of the pits formerly oiJeu are now closed or water-logged. 

 Kilbride, co. Wicklow, the locality given in the ' Fossil Catalogue ' of 

 the School of Mines, London, for some of Captain James' rarer fossils, 

 has not been worked for forty years past, I am told by Mr Gawan, who 

 has been resident there during that time, and directed my attention to 

 one or two exposures of gravel. Only the local upper gravel with sand 

 was visible. In the same manner as the Slaney in the south cut through 

 the series since their deposition, so also has the Ovoca in the north, the 

 ilbride gravels being on the Wicklow side of the river. 



(1) Shells collected by A. Bell in the Wexford Gravels. 



Buccinum undatum. 

 Cj'praea europea. 

 Dentalium entalis. 

 Fusus gracilis. 



„ antiquus. 



,, contrarius. 



„ islandica jav. 



„ Menapii, M.S. (n. sp.) 

 Fissurella grasca. 

 Murex erinaceus. 



Nassa incrassata. 

 „ reticulata. 

 „ nitida. 

 ,. pj-gmsa. 

 Natica greenlandica. 

 Purpura lapillus. 



„ incrassata. 

 Pleurotoma pyramidalis. 

 ,, rufa. 



„ (var. semicostata.) 



