J. W.Jackson & W.E.Alldns — Quartzose Conglomerate. 59 



disappearance of the ice the laud again slowly rose, reintroducing 

 glacial conditions. This is supposed to have taken place four times 

 in succession, each succeeding cold period being less severe than 

 the last. 



In Europe there may appear to be some evidence in favour of the 

 view that the periods became less cold as they succeeded each other; 

 but in America there is little evidence of this kind. In Europe 

 during the first cold period the Straits of Dover probably did not 

 exist and the ice advanced over the area now occupied by the North 

 Sea. The opening of the straits at a later period much restricted the 

 advance of subsequent ice-sheets. 



I have suggested that the Glacial Period was the result of two 

 agencies acting together. Separately they could not produce the 

 required conditions ; but jointly they could. It is well known that 

 the great polar cyclones of the earth are acting in direct opposition 

 to the gradient of temperature on the earth's surface, and produce 

 the poleward flow of the air in temperate regions. 1 The energy 

 which keeps these cyclones in action is very probably cosmical and 

 may undergo periodic fluctuations. In pre-Tertiary times the 

 distribution of land was seldom such as to lower the temperature 

 sufficiently to enable a temporary decrease in the strength of the 

 polar cyclones to produce a glacial period. In Pleistocene times, 

 however, the polar areas became so continental or landlocked that 

 the periodic waning and strengthening of the polar cyclones led to 

 alternating cold and warm periods. 



Winds from the Poles towards the Equator do blow, of course, but 

 they are not anticyclonic. They are merely surface winds, or winds 

 resulting from travelling cyclones. The great cyclonic low-pressure 

 a.reas of the Poles persist throughout the year. 



III. — On the Discovery of a Quartzose Conglomerate at Caldon 



Low, Staefs. 



By J. Wilfrid Jackson, P.G.S., and W. E. Alkins, B.Se. 



DUPING a visit to the limestone quarries at Caldon Low last 

 September we had the good fortune to discover an interesting 

 exposure of a quartzose conglomerate containing numerous fossils. 

 The bed was exposed in a strong joint-face running approximately 

 N.N.W. to S.S.E., at the northern extension of the quarry on the 

 north-west flank of the Low, just beyond the mineral line of the 

 North Staffordshire Pailway. The altitude is 'about 900 feet O.D. 

 The conglomerate apparently extended some little distance to the 

 south-west before the opening of the quarry, as we ascertained that 

 some 20 or 30 yards had been removed in gaining access to the 

 limestone behind. It appears to extend for some distance round the 

 flank of the Low towards the north-east. 



In the section exposed the conglomerate did not appear to possess 

 definite bedding in its lower portion ; but higher up the slope of the 

 hill, on the S.S.E. side of the section, it was seen to pass upwards 



1 Phil. Mag., vol. xxx, pp. 13-33, July, 1915; vol. xxxi, p. 399, April, 

 1916 ; vol. xxxv, pp. 221-36, March, 1918. 



