1905-1906.] 329 



clays upon which the Esker rests. Hence the value of these 

 records. At Greenisland we counted 300 boulders, each 100 

 taken at random, from a different level in the section : all were 

 erratics, and the proportion in which they occured varied in a 

 definite ratio for each level — 100 at Castle Espie, similarly 

 proved to be all erratic boulders. In the Black Mountain deposit, 

 discovered by Mr. Bell, the only place I have seen in our 

 district with distinct upper and lower boulder clays (the latter 

 being so hard that hammer and chisel were required to extract 

 its stones), 270 out of 274 were erratics; at Cloghanport 331 

 out of 339, with percentages at other localities varying down to 

 17 per cent, at Carnmoney and Bloody Bridge, XXXV. The 

 latter has been considered a moraine deposit, and contained 

 only a few travelled rocks, including a fragment of the 

 porphyry dyke on the shore, 100 feet beneath, but no chalk nor 

 flints were found in it. 



Another point noted in our schedules is the frequent oc- 

 currence of some erratics and rarity of others. Of 107 varieties 

 we found 26 at Dromore, XXXI., 27 at Ballyholme, 28 at 

 Cloughfin, 33 at Newry, and 44 different rocks — almost 40 per 

 cent, of the total list of rock varieties in the brickfields round 

 Belfast, 10 out of 44 being isolated records of erratics, not as 

 yet found elsewhere, showing the value of patient, persistent 

 investigation, such as Mr. Bell devoted to them. Glacialists 

 who may wish to study the matter more fully are referred to the 

 tables accompanying this summary, and can examine our valu- 

 able list and collection of erratics at the Museum and the 

 manuscript schedules with detailed descriptions of localities 

 investigated. 



When commencing work, we were frequently assured that 

 we would, never find erratics north of their place of origin. Our 

 experience does not at all bear out this assertion, which 

 postulates a simple, southward ice-flow, and omits to reckon 

 with radiating local systems of glaciation that may have per- 

 sisted over high ground prior to, and long after, the great 

 central plain of Ireland and the Irish Sea were free from solid 

 ice. A scrutiny of the tables giving the compass direction of 



