1866.] HAEMER A THIRD BOULDER-CLAY. 87 



transported masses imbedded in the contorted Drift of the Cromer 

 coast, especially that in which the limekiln is worked nnder Cromer 

 Lighthouse, — galls of dark sand occurring in it there, as those of 

 clay do here. 



To what precise action these galls are due, or what the clay is 

 that fills them, it is difficult to say; but the appearance of the section 

 impresses me strongly with the conviction that we have here evi- 

 dence of the passage of a glacier over the surface of the chalk, — the 

 adhesion of the base of this glacier, in places, to the saturated 

 chalk, caused by means of the intense congelation, having, during 

 the glacier's onward motion, dragged up the chalk until the cohesion 

 of the chalk itself balanced the dragging action, and the mass parted. 

 Connecting this section with the masses seen in the contorted portion 

 of the Lower Drift on the coast- section, we seem to see the process 

 under which these masses were dragged from their matrix, and 

 carried onward to the sound into which the glacier disembogued. 

 It is probably in the retirement of this glacier before the increasing 

 warmth which ushered in the Middle-Drift period, that this thin 

 bed of Lower Drift, which spreads over so much of Central and "West- 

 central ISTorfolk, had its origin, the streams of chalky silt which 

 the grinding of the glacier over its bed produced having been spread 

 out as the glacier receded *. 



In speaking of a glacier, I do not refer to any such as those oc- 

 curring in mountain-regions, but to one enveloping the whole sur- 

 face of the country, as described by Dr. Sutherland, and now cover- 

 ing the land around Baffin's Bayf. The distribution of the three di- 

 visions of the Drift seems to show that much of the centre and 

 south-west of ISTorfolk was, during the Lower-Drift period, the seat 

 of this capping glacier, and that its principal seaward termination 

 was in the direction of Cromer, where the bulk of its moraine was 

 spread out under the sea, the finer silt being carried south-eastwards 

 to form the brickearth continuation of it which stretches as far as 

 the northern border of East Suff'olk, and that much of the seat of 

 this glacier, from its more elevated position, remained above water 

 diuing the whole Middle-Drift period, only passing under the sea 

 when the great submergence of the Upper-Drift (c of fig. 1) or true 

 Boulder-clay j)eriod set in. 



3. On the Existence of a Third Boitlder-Clat in Norfolk. 

 By F. W. Harmer, Esq. 



[Communicated by Searles V. Wood, Jim., Esq., F.G.S.] 



(Abridged.) 



The deposit which is the subject of this paper is shown in a pit near 

 Trowse junction, a mile to the south of Norwich. It consists of a 



* In this view the inland bed {b of sect. 1) would only represent the very 

 uppermost part of the Contorted Drift of the coast, the rest of that Drift, as well 

 as the subjacent Boulder Till, being represented by the glaciated land-surface. 



t Quart. Journ. Greol. Soc. vol. is., p. 301. 



