586 



MR. 0. A. SHEUBSOLE ON SOME HIGH-LEVEL [NoV. 1 898, 



table, which states the percentage of the various stones in the 

 saioples examined: — 



Flint-pebbles 



Subangular flints of small size 



S m all quartz-pebbles 



Sarsen 



Lydite(?) 



Friable rocks 



Cheqiiers 



Cadmore 



Lane 





Farm 



End 



End 





(600 feet). 



(600 feet). 



(600 feet). 



(500 feet). 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



85 



85 



io 



88 



9 



4 



20 



10 



6 



10 



3 

 1 



2 



... 



'i 



1 





A pebble of chert, from the gravel at Nettlebed, was submitted 

 to Dr. G. J. Hinde, F.R.S. He found it to be ' packed full of the 

 detached spicules of various forms of siliceous sponges — simple 

 needles, trifid spicules of tetractinellid sponges, also hexactinellid 

 spicules. There are no forms sufficiently distinctive to determine 

 the formation from which the chert may have come, but not 

 improbably it is of Carboniferous Limestone age.' Dr. Hinde 

 informs me that there are pebbles of the same kind of sponge-chert 

 in gravels of the so-called ' Westleton Beds ' at Potter's Bar. 



This gravel is included in the ' Westleton Shingle ' of Sir J. 

 Prestwich. That term has not been adopted here, not from any 

 want of respect to the judgment of so eminent a geologist, but in 

 order that the facts may be more conveniently presented. 



Looking at the waste that it has undergone, its elevation, and its 

 composition (which approximates to that of the Eocene pebble-beds), 

 it must certainly be regarded as an old deposit. Whether it is an 

 extension of the Westleton Beds is a point upon which I do not 

 feel competent to offer an opinion. A section, apparently of the 

 latter, which was seen in the cliff near Southwold, was not unlike 

 it in general composition, except that, in the portion examined, 

 more than half the stones were subangular. This is not exactly 

 what one would expect to see if the land lay farther west, and 

 if both deposits were laid down in the same sea. 



III. The Goring Gap Gravel. 



The last summit of the Chilterns at Woodcote is capped by 



gravel which may be seen in an old gravel-pit opposite the inn, at 



a level of a little over 600 feet. This has been fully described by 



other observers. It may be convenient, however, to state here its 



composition, as arrived at by counting the stones in a portion of 



the gravel : — -d , 



^ Per cent. 



Flint-pebbles 42 



Subangular flints 52 



Quartz-pebbles 3 



Sarsens "5 



Pale quartzites 05 



Sandstone and other sedimentary rocks 1 



Chert 1 



