590 MR. P. G. H. BOSWELL ON THE [Dec. 1913, 



and from the nature of the beds disturbed lends itself to more 

 detailed treatment. 



Gipping Valley. — The plateau around the valley is at a level 

 of 150 to 200 feet O.D., and to understand the relief of the district 

 reference must be made to a coloured contour-map (PI. LY, fig. 1). 

 The valley proper is mainly the portion below the 100-foot contour ; 

 and it will be seen that, in places, all down the valley on both 

 sides 'bluffs ' or ' spurs ' of land project inwards. 1 In most cases the 

 bluff is indicated by the swelling of both the 50-foot and 100-foot 

 contours, but sometimes by the former only. Over twenty definite 

 cases of disturbanee of some or all of the beds of the district 

 (Chalk, Thanet Beds, Eeading Beds, London C]ay, Crag, and Glacial 

 Beds) were recorded by the officers of the Geological Survey, 

 some being referred to glacial action as a cause. 2 More recent 

 work has been carried out by Mr. George Slater, exceptional oppor- 

 tunities having arisen in recent years for the detailed study of 

 the remarkable glacial phenomena in this valley. 3 



When the exact positions of all these sections showing intense 

 disturbance and buttressing are plotted on the contoured map, 

 it is found that each is located upon one of the spurs mentioned 

 above, and that there are no records of any considerable disturbance 

 in any of the numerous sections exposed on the plateau. The 

 presence of disturbance upon every important spur down the 

 valley (as noted by the Geological Survey, Mr. Slater, or myself), 

 and the absence of such elsewhere, precludes the possibility of mere 

 coincidence. The position of such recorded disturbances (but- 

 tressing, contortion, shearing, transportation, etc.) is shown in 

 each case on the map (PI. LV, fig. 1), by an arrow marking the 

 direction from which pressure appeared to come, as determined 

 by the phenomena there observed. In detail, the chief places 

 are : — 



(a) Gallows Hill, Barking, near Needham Market. 4 — Actually 

 there are two hills bearing the same name. The sections show- 

 ing disturbed beds on the more northern of the two spurs have not 

 yet been described in detail, although good sections are at present 

 visible there. Those on the more southerly spur and on the 

 sides of the rail way -cutting through it are now covered with 

 talus and grassed over, but were noted by Sir J. B. Phear 5 and 

 by the officers of the Geological Survey. 6 



1 Sir J. B. Phear seems to have observed some of these, and termed them 

 'sand-cliffs' in his 1856 paper (1) p. 434, &c. 



2 Mem. Geol. Surv. 1881 (8) & 1885 (10), pp. 9, 18, &c. 



3 Slater, 1907 (22) p. 1S6, & 1911 (32) p. 11. 



4 Many of these projecting spurs into the valleys have received the name 

 ' Gallows Hill ' in Suffolk, the reason being obvious. Their conspicuousness 

 also accounts for the term ' Beacon Hill ' applied to many of them. Some in 

 the Gipping Valley are alleged to have been fortified by the Romans, and used 

 as stations overlooking and guarding the Boman road which runs up the 

 valley on its course to Norwich. 



5 Sir J. B. Phear, 1856 (1) p. 436. 



6 Mem. Geol. Surv. 1881 (8) p. 7. 



