ON A PREHISTORIC SITE AT BISHOP'S STORTFORD. 133 



Method of procedure: — 



(i) A trench four feet deep was driven to the right, and a similar 

 trench to the left, from the line of the present streamlet below the 

 pond well into the undoubted London clay in situ behind the ' rubble- 

 drift ' ; 



(ii) A trench has been dug below the pond up the line of the 

 ancient gully, which was found completely choked with remanie clay 

 of the character of blackish bog-silt. At a depth of four feet below 

 the present surface of the hill-slope a fine angular flinty shingle with 

 several erratics was dug into, clearly marking the line of the ancient 

 gully which the stream had cut into the flank of the hill in post- 

 glacial times. This was observed to be in a line with similar in- 

 dications of the ancient line of the stream, across which the trunk of 

 the horse was seen to have lain when it was removed in 1909. It 

 may be said that no one who has had extensive observation of the 

 Eocenes could recognise these phenomena as having anything to do 

 with the London clay, which constitutes the solid geology of the hill 

 behind, as it had been proved in the trial-borings of the autumn of 

 1909, and exposed in recent excavations for building along the same 

 contour of the hill slope. Of the ' finds ' from this trench on the 

 arterial line of the ancient gully the following list is given: — 



A. Mammalian remains : — 



Four very rotten fragments of split marrow-bone, one lower 

 premolar of Equus (broken). 



B. Human artefacts : — 



Fragment of a gritstone hand-mill, two fragments of 

 extremely primitive half-baked tiles; one clinker; five or six 

 (apparently) ' pot boilers ' ; about a dozen flints, possibly recog- 

 nisable as ' cores ' or ' scrapers, ' two of them ' patinated. ' 



The erratics from the three trenches include : — 



Two good-sized boulders of volcanic ash, small boulder of 

 weathered dolerite, a sub-angular fragment of jasper, four moderate- 

 sized pebbles of vein-quartz, two rolled fragments of coarse white 

 gritstone, a rolled fragment of Bothlschiefer ? (Permian), a slab of 

 red ferruginous sandstone (Jurassic?) two inches thick; a slab of 

 white fine-grained sandstone (Keuper?) one inch thick. 



To these must be added fiints without number, nearly all in a 

 highly weathered condition, some extremely so, several showing the 

 etching action of organic (humus) acids, while others bear unmistakably 

 the marks of long surface-exposure (possibly during the great Miocene 

 elevation) before they were picked up by the early ice, which deposited 

 the glacial drift which caps the hill, and from which these erratics must 

 have been brought down, since the deposit is at a higher level than the 

 true chalky boulder-clay of the district. Eight at least of these 

 highly altered flints have been not only bleached but scaled, after the 

 fashion of those brought years ago by Captain H. G. Lyons, F.B.S., 

 from the Egyptian desert. Scarcely a fresh flint was found in the 

 course of the excavations, and it may be inferred that these extremely 

 altered flints have been transported in many cases by ice-agency from 



