110 [Proc. B.N.F.C, 



their valves unit 3d. The presence of these perfect Ledce was 

 known to General Portlock, and convinced him, as it did after- 

 wards Mr. S. A. Stewart, that the Boulder Clay was a marine 

 sedimentary deposit. 



Foraminifera in Boulder Clay are usually much smaller 

 in size than recent British species; this is what might be ex- 

 pected to occur in a climate so rigorous as must have prevailed 

 during the glacial period. Several of the species, however, 

 both here and at Knock Glen, near Belfast, are fairly large 

 in size. The following are the most notable in this respect : — 

 Miliolina seminulum, Nonionina orbicularis, and Polystomella 

 arctica. No other locality for Boulder Clay in the United 

 Kingdom has yielded Foraminifera in such profusion, and the 

 clay at Knock Glen, near Belfast, has them in nearly equal 

 numbers. At these two localities also Foraminifera have been 

 obtained which are now only known as recent British species 

 from collections off the West Coast of Ireland and in one or 

 two instances from the West Coast of Scotland ; some have 

 also been obtained at a few other localities. Those found at 

 Woodburn were Cassidulina Bradyi, Lagena fimhriata, and 

 Nonionina orbicularis. 



The profusion of Foraminifera at these two localities, the 

 large size of some of the specimens, the occurence in them of 

 West of Ireland species, the fineness of the clay and its 

 freedom from stones, would lead us to infer that the Boulder 

 Clays at these places were deposited in deep and quiet water, 

 below the disturbing influence of ice action, and when marine 

 conditions were somewhat similar to what now prevail off the 

 West Coast of Ireland. 



Amongst the rarer forms which occur are — Bulimina 

 elegans, var. exilis, B. minutissima, Bolivina obsoleta, B. ser- 

 rata, Cassididina Bradyi, Lagena depressa, L. fimbriata, L. 

 castrensis, Frondicularia Millettii, Discorbina minutissima, D. 

 tuberculata, Truncatulina reticulata, and Nonionina orbicu- 

 laris. 



To ascertain how far floatings could be relied on for giving 

 conclusive results, one ounce troy of this clay was examined 

 with great care. The following table gives the result of this 



