1905-1906.] 327 



fields. Subsequently we ascended the Cave Hill, and found a 

 small deposit in the hollow behind M' Art's Fort, more than a 

 thousand feet above the sea, containing erratics of flint and 

 several foraminifera, but the loftiest record fell to Mr. Stewart, 

 who discovered fossiliferous boulder clay between 1,300 and 

 1,400 feet on Divis Mountain! 7 



In the recent geological survey memoir of the drifts around 

 Belfast, published in 1904, we are told of Lake Belfast, 8 a vast 

 expanse of fresh water, formed during the waning of the glacial 

 period by flood waters from melting ice in the Lagan Valley, 

 dammed back by a barrier of ice that still existed across the 

 head of our present Lough. The waters of this lake escaped 

 by the Dundonald Valley, emptying themselves into Strangford 

 Lough. The gravel pit at Longhurst, XXVI., Neill's Hill, 

 XXII., Morrison's Sandpit, XXIII., and other deposits of Dun- 

 donald Valley, XXIV., all belong to this late glacial period. 

 Possibly these southerly floods bore along much floating ice, 

 which may partially explain the occurrence of many rocks from 

 the Mourne districts in the Belfast drifts, in the Dundonald 

 sands and gravels, and along the wave-worn boulder clays of 

 Strangford Lough, where they are mingled with granites from 

 Pomeroy, Slieve Gallion, and Slieve Croob, rhyolite from Tard- 

 ree and eurite from Annalong, one unique specimen embedded 

 in boulder clay at Castle Espie, XXVIIL, being identified by 

 Mr. M'Henry as a primary conglomerate occurring in Cavan, 

 Monaghan, and Armagh, We found Castle Espie limestone as 

 an erratic southward as far as Killough, where our geological 

 section held a pleasant Christmastide excursion in 1897. This 

 Killough deposit of stiff boulder clay and conglomerate, partially 

 turned to calcrete, occurs close to Silurian rocks, whose splendid 

 glaciation disappears below the waves ; yet no microzoa were 

 found in the clay from this section, although the spray is 



7. The Occurrence of Boulder Clay on Divis. Proc. B.N.F.C. (2), IV., p. 



215 (1894-5). 



8. The Geology of the Country Around Belfast. Mem. Geol. Surv. Irel. 



(1904), pp. 50, 62, etc 



