ON SOME PLATEAU DEPOSITS AT FELSTEAD AND STEHBINO. 1 33 



occupy the highest ground. That is to be found about a furlong to 

 the nortli-east, and is about six feet higher, and is of Boulder Clay. 

 The gravel is about sixty to seventy feet above the river. 



This gravel rests upon the Boulder Clay, and as in its composition 

 it has, so far as I can see, no bond of connection with that deposit, 

 it could not well have been derived from its waste. It does, how- 

 ever resemble local Glacial Gravel (that underlying Boulder Clay), and 

 may. therefore, reasonably be supposed to have been derived directly 

 from it. But when we come to inquire how the transport was effected, 

 and from what direction it came, we are met with a great difficulty. 

 The promontory at the time of the deposition of the Boulder Clay was 

 here probably surrounded on three sides by a considerable valley.' 

 We should, therefore, be taking an unwarrantable position in su[ - 

 posing the Boulder Clay to have filled up the valley here, and so to 

 have formed a bridge over which the gravel could pass, although it 

 may have done so. It would be better to suppose that the gravel 

 came from the west, where Glacial (travels are now exposed at a 

 mile distance, but at a somewhat less elevation. 



The forces engaged in this transport must have been prodigious, 

 whether submarine or due to melting ice after the elevation of land 

 (there would certainly seem to be a hiatus between the underlying 

 Boulder Clay and the gravel as shown by the sharpness of the 

 juncture). Whatever may have been the agency, it was sufficient to 

 transport boulders of upwards of seven pounds in weight.'- 



The onus rests with me to show that the Post-Glacial has no 

 bond of connection with the Boulder Clay. This is difficult to prove, 

 but the same difficulty applies to the Gravel underlying Boulder Clay. 

 Anyone well conversant with the two deposits cannot possibly mis- 



I This I infer from the circumstance th u the stream now occupies a depression in the London 

 Clay, and that Boulder Clay in at least two places extends to nearly the bottom of this depression 

 on Molehill Green, and at the same elevation London Clay is reached at a depth of less than ten 

 feet. Continuing down the valley, but more towards the west, Boulder Clay extends nearly to 

 the bottom On the opposite side of the river, at Willows (Jreen, at about the same eleiiation 

 as at Molehill Green, Lon Ion Clay is exposed as shown on the map, and at a little norlh-wesi of 

 this, at a much less elevation, Boulder Clay resls on the slope. [On this slate neni Mr. Whitaker 

 remarks as follows : — " This is clearly a case showing the irregular deposition of Boulder Clay, 

 whi h cuts into London Clay in a sort of irregular channel. But the valley has been worn out 

 since the deposit of Boulder Clay, and is cut through it and the gravel to the London Clay. The 

 mapping distinctly makes the gravel underlie the Boulder Clay. Of course there ni.iy be later 

 gravel also. — W. Whitaker."] That marked on map as Glaciil Gravel at this spot, is probably 

 Post-< Hacial, and is thinly spread at places. Li the absence of sections which did not then exist, it 

 could hardly have been marked otherwise than as (jlacial. That at Peak's Hall, a little further 

 up stream, \ cannot as yet determine. 



1 may mention that I have notes of similar depressions in the London Clay which are'partly 

 occupied by Boulder CI ly, extending along the present bed of the Chelmer. I hope to put them 

 on record later. 



2 I only found one stone weighing as much as forty pounds, and it is />ossible that this may 

 have been dug from the underlying Boulder Clay, but Lfeel quite sure that this was not so. 

 Although I broke the Boulder, I could make nothing of it, as it did not agree with any rock that 

 I had before -.een. 



