410 Fisher— Roswell Hill Clay-pity Ely, 



present. I was quite confirmed in that opinion by what I saw the 

 other clay.^ 



The mass seems to be much of the shape of a great punt, the prow 

 of which is directed towards the west. The mass is so thick to- 

 wards the stern, i. e. at the eastern end, that they have not dug 

 through it, but towards the centre the workmen told me they found 

 a " snuff-coloured hard clay," at the bottom of the pit beneath the 

 Chalk, '' hard clay" being the term by which they designate the 

 Boulder-clay. Towards the western end of the exposure of the Chalk 

 this clay may be seen beneath it in the section, enclosing angular 

 lumps of chalk. Towards the cottage on the bank the Chalk thins 

 out to nothing, the Boulder-clay passing beneath it. 



I believe the Lower Green-sand blocks which occur on the south 

 side hereabouts to be no more in situ than the Chalk. 



The Boulder-clay between the Chalk and Kimmeridge clay shows 

 tortuous streaks of bedding, (some of them chalky,) in a highly in- 

 clined position. They seem to have been originally horizontal as 

 well as the Chalk. But no one who has seen the Cromer cliffs will 

 think any mode of bedding too strange to occur in the Boulder-clay, 

 or call in the aid of a fault to account for it. 



The second part of the enquiry relates to the occurrence of this 

 mass of Boulder-clay in juxtaposition to the Kimmeridge-clay. The 

 question lies between a fault and a great channel of erosion, made 

 for itself by the Glacial drift. 



The only evidence upon this point to be obtained in the pit is by 

 examining the junction. If the country were mapped, and a fault 

 affecting other strata traced through the pit, this would settle the 

 question in favour of a fault. There seem to be disturbances in the 

 neighbourhood. We have Oxford clay, for instance,^ at the bottom 

 of the hill near the railway station, where Kimmeridge-clay would 

 have been more natural. And other places might be named ( Aldreth 

 and Alderforth). But that faults affect the Oolite affords only a slight 

 presumption that they will also affect the Boulder-clay. With re- 

 gard to the evidence to be obtained at the spot itself, I first of all 

 attempted to examine the junction by digging in the side of the pit ; 

 but I found that, owing to a line of springs thrown out by it, the 

 Boulder-clay has slipped, so that I could not reach the undisturbed 

 ground. This circumstance misled me when I examined the place 

 in 1856, and made me suppose the junction showed slikenside, which 

 was really due only to a recent slip. I then searched for, and found 

 the junction in one of the banks left by the workmen to exclude the 

 water as they dig. 



Here I found it well defined; but I could not discover any of those 

 symptoms of pressure, or the polished surfaces, which are always 

 observed to accompany a fault. As far then as the evidence goes it 

 is against the occurrence of a fault, and points to the Boulder-clay 

 occupying a trough, which it has ploughed out for itself in the old 



1 See also Note 2, p. 52. 



- I have since learned, however, that a well at Ely commenced in the Kimmeridge 

 soon reached the Oxford clay with a thin stony band containing iV^rtVicco intervening. 



