450 Alfred Bell — Post-glacial Drifts of Ireland. 



Witli the fauna of tlie Larne gravels I am disposed to associate 

 that of the best known of the submarine shell-banks (the Turbot 

 bank) Ijang off the mouth of Belfast Bay northwards. Several 

 conchologists are disposed to claim the shells as recent forms ; but so 

 many are unknown in British waters that it is worth considering 

 whether, as has been suspected, there is not here a richly-fossiliferous 

 Post-Tertiarj'- deposit. 



I owe to Mr. Waller (Tyrone) and Mr. Stewart (Belfast) the 

 opportunity of looking over some parcels of stuff dredged off the 

 bank. None were live shells, but all had a porcellanous or hyaline 

 glaze, and were devoid of colour, differing in these respects from 

 their recent analogues. 



Of 220 species listed from the bank, not more than five per cent, 

 were found living — an exceedingly small proportion. Amongst the 

 species, all of which are small, intermixed with Celtic and southern 

 forms, are nine or ten whose congeners now live in the northern seas ; 

 and I submit that if a deposit containing such forms as Buccinum 

 cyaneum, CeritMum niveum, Colwmhella Holbdllii, Margarita cinerea, 

 M. pusilla, M. undulatus, Natica affinis, Scalaria Eschrichtii, and 

 Trophon claiJiratus, were placed ever so little above the sea-level, 

 instead of, as this is, 150 feet below, we should at once relegate it to 

 some part of the Post-Tertiary series, as I propose doing in this case. 

 The intermixture of southern forms with those of higher latitudes 

 does not interfere with this supposition, since they are equally 

 present in the Killiney Drifts, the Lancashire Drifts, and in some of 

 the Scottish Clyde beds, especially the one near Greenock. Indeed, 

 amongst a parcel of minute shells and shelly clay from the latter 

 place, I detected the fry or extreme young of some living Mediter- 

 ranean forms, — Conus Mediterraneus and Cardita trapezia. 



Forty Turbot-bank forms are still unrecorded from any British 

 Post-Tertiary deposit, but twenty of these are well-known Crag 

 species. 



Another argument in favour of the fossiliferous nature of this bed 

 is the fact that few, if any, of the northern species occur in the other 

 shell-banks in the immediate neighbourhood. 



South of the Mourne Mountains the calcareous gravels and clays 

 set in near Balbriggan, and are well developed from thence south- 

 wards by Louth Finglass, up the valley of the Liffey into Kildare, 

 and through Co. Carlow, which is covered by thick deposits, dimin- 

 ishing very much towards the south into Wexford, by the valley of 

 the Slaney, and into Kilkenny by the valley of the Barrow. 



On the coast the drift sets in on the summit of Killiney Hill 

 (400 feet) in a thin bed of gravel, thickening southwards towards 

 Bray, forming low bluffs or cliffs, passing some little way up the 

 rivers or streams near the coast, flanking the north-west side of the 

 greater Sugarloaf to 600 feet (shells), thence to Bray Head. From 

 the southern side of the Promontory the deposit extends for about a 

 mile, diminishing from a thickness of " 200 feet to the level of the 

 sea-shore" (Dr. Scouler), and passing in "a, great but interrupted 

 plain towards Wicklow " (Oldham). 



