1904- Praeger. — Round about Lake Belfast. 145 



not correspond with the present drainage of the country ; 

 they do not form recognizable delta-fans at the points where 

 the existing streams would have debouched into the old lake ; 

 but probably, when the sands were laid down, the drainage 

 was largely determined b}^ the ice which still held sway 

 on the rising grounds around. The fine esker of lyis- 

 burn, which, no doubt, represents one of these englacial 

 drainage channels, shows how the local drainage, before the 

 final passing away of the ice, differed from that obtaining at 

 present. The thickness and extent of the gravels of the old 

 lake-margin, and of the fine sands and clays of its deeper 

 portions, bear witness to a very considerable inflow of water. 

 How " I^ake Belfast" was drained — whether through the 

 Dundonald valley into Strangford Lough, or in some west- 

 ward direction — is undecided, since no opportunity presented 

 itself of examining the southern limit of the assumed lake- 

 deposits, which are still in full force on the edg<^ of the map 

 at lyisburn ; but the nature of the uppermost drifts in the 

 Dundonald valley, and the great delta-like masses of late 

 Glacial sands and gravels below Comber, strongly suggest that 

 here the waters of the lake escaped into the ice-free inland 

 waters of Strangford Lough. Owing to the arbitrary limits of 

 the work of the officers of the Survey, a really fascinating 

 problem is thus propounded without being definitely solved — 

 one which is excellently suited to the talents and opportunities 

 of local geologists. 



We have already exceeded the usual limits of a review in 

 this Journal, and must pass rapidl}^ over a few of many in- 

 teresting points not yet referred to. The curious little gorge 

 or dry gap west of Holywood glen, and the gravel mass by the 

 stream further up, point to a small ice-margin lake with lateral 

 drainage in the glen ; and Mr. W. B. Wright finds several other 

 similar dry gaps in the north-west of the district, on the 

 basaltic plateau, or etiesta^ to use a convenient American term 

 introduced in the Memoir, and applied to a steep escarpment 

 backed by a long dip-slope. 



In the Dundonald valley, Mr. H. B. Muff records (p. 113) a 

 sand-pit yielding many fossils near Solitude, which the 

 Geological Section of the Belfast Field Club might do well to 

 plunder ; and Mr. Seymour refers (p. 1 20) to an unusually large 



