86 REPORT — 1875. 



teresting ; and No. 1 ia probably the next in interest. They all rest on a 

 slate subsoil, •which crops up in certain places. 



That the stones have travelled some distance there cannot be a doubt ; for 

 whilst they are detached and trappean, they occupy an area having slate as 

 its subsoil. 



That thoy have not travelled far is highly probable, from the fact that trap 

 occurs ill situ on almost every side of Englebom-ne, at distances varying from 

 3 miles to 2-2 miles, to say nothing of numerous remoter masses. Of those 

 in the immediate neighbourhood, one of the largest, about 1*6 mile north, 

 measures 1"7 mile in length by 3 miles in greatest breadth, and is separated 

 by the little river Harber from a much smaller mass on the west side of that 

 stream. 



Their size is so inconsiderable as to leave no room for doubt as to their 

 mobility imder the action of waves or violent floods ; but to this mode of 

 transport there is the grave objection that, with the exception of No. 2, they 

 are not suificiently rounded, even though due allowance is made for their 

 hard and tough character. 



It appears impossible to account for the grooves otherwise than by sup- 

 posing them to have been produced by ice-transportation. That the famous 

 granite boulder of Barnstaple Bay was ice-borne was shown in a previous 

 licport. That Bovey Heathfield was, during a very recent geological period, 

 cold enough to be the habitat of the arctic and alpine Betula nana is a well- 

 established fact, and the thick accumulation known as the " Head " on Bovey 

 Heathfield is explicable on the glacial rather than on any other hypothesis ; 

 and were it not that glacial scratches have never been detected on the lofty 

 tors of Dartmoor, where, if anywhere in Devonshire, they might have been 

 expected, rather than on the low grounds about Engiebourne, more certainty 

 would attach to the opinion that these scratched stones are proofs of glacial 

 conditions in South Devon, aud that, as such, they contribute largely to the 

 solution of the problem of the New Eed Sandstone boulders of Waddeton, 

 from 5 to 6 miles further east. 



Heetfokdshiee. 



Mr. E. P. Greg, F.G.S., reports a group of small boulders in the parish of 

 Westmill, near Buntiugford, in the N.E. of Hertfordshire, and 30 miles due 

 north of Greenwich. 



About 1 foot aud 2| feet. Several found in same field, some 50 yards or 

 BO apart. 



Much rounded to subaugular, angular, and slightly oblong in general form. 



No groovings or striations visible. 



Nearest point certainly Derbyshii'o. 



90 to 100 miles distant exactly N.E. 



The boulders are composed of ordinary Mountain-limestone. 



320 feet above sea ; about 70 feet above river Rib. 



No others have been noticed in Hertfordshire, except three or four in tliis 

 cue field, which lies in a slope, with east aspect, about 70 feet above the 

 river Eib, which runs here to the south. 



The boulders in question were not exposed on the surface, but turned up 

 in draining. Drains 3 feet deep. Soil a clayey loam overlying the chalk, 

 which in these parts is more or less covered with clay and gravel to depths 

 of 6 inches to 30 feet or more. 



