378 E. W. Skeafs: 



Distribution and Nature of Pebbles in the Deposit. 



The vertical section exposed in the main shaft at F on the map 

 shows from above downwards. 



Silt, 18 inches. 



Gravelly wash, part angular, part rounded — 2 feet — 2 feet 6 

 inches. 



Volcanic agglomerate, with a few large pebbles and scattered 

 rounded quartz grains — IS) feet — 19 feet 6 inches. 



At shaft S, sunk by Jenkins and Beilski, the surface material 

 tontained many jiebbles, but the material brought up in sinking 

 the shaft consists almost entirely of fragmental volcanic material 

 with small quartz grains scattered through it. Some fragments of 

 altered Ordovician sandstone occur, and one of these is described 

 later. It was reported to me that a large boulder was found near 

 the bottom of the shaft, but of this I have no personal knowledge. 

 The surface outcrops of the deposit generally show no bedding or 

 sorting of the material, and contain abundant pebbles, some angu- 

 lar, some rounded, and some facetted, of various rocks, including 

 quartzites, shales, and vein quartz. The pel)bles occur with their 

 longer axes irregularly disposed. In places rude bedding of the 

 material is indicated principally by bands of varying colour. Mr. 

 Dunn lias referred to the occurrence of veins of chalcedony in the 

 deposit. I found one such piece, evidently formed since the 

 ■deposit, filling a cavity in the material and showing concentric 

 banding, indicating deposition from solution. 



The distribution of the pebbles suggests that they are only abun- 

 dant near the surface. Mr. Dyason and myself, however, descended 

 tlie main sliaft at F on tlie map. and found. eml)edded two inches in 

 the wall of the shaft 1!) feet l)elow the surface, a (juartzitc pcl)l)le, 

 which is polislied and facetted and almost certainly of glacial origin. 

 Minute, rounded and angular quai-tz grains are not uncommon in 

 the volcanic niatri.x wherevci' we I'xaniinrd it. .Vniong the (luai'tzite 

 pebbles in the siiperhcial part of the de])osit a number wen' found 

 which, while rounded, were also ))olished as if l»y glacial attion. 

 while one shown in Plate xxxii.. Fig. 1 is a (piartzite pebble, not 

 only definitely facetted but showing on one face distinct glacial 

 striations. Thei'c vnn be no dou])t theiefoie that Mr. Dunn was 

 right in descril)ing the pel)bles as glacial, although he did not 

 obtain evidence, such as is described above, of facetting and stria- 

 tion among the pebbles. 



