1866.] 



FISHEK WAEP. 



557 



so up the hill. The drifted fragment is much distorted, but never- 

 theless not scattered. There are similar patches of this bed in the 

 trail in an old Crag-pit on the Saxmundham road, about a mile and a 

 half from Aldborough. 



A similar case was seen by Mr. Boyd Dawkins and myself at 

 Walton-on-the-Naze, where an angular lump of London Clay, about 

 eighteen inches in diameter, was entirely enveloped in a mass of 

 gravelly trail. 



Fig. 5. — Section across a furrow of Trail covered hy Warp, left 

 standing after the removal of the surrounding gravel for ballast, 

 Wivenhoe, Essex. 



a. Warp. 



b. Trail. 



The position of the pebbles in the trail, and still more so the con- 

 torted but unscattered condition of incoherent material, show that 

 the trail has been transported in a plastic state (as mud) moving by 

 its own gravity, or else pressed onwards by some other agent. 



Fig. 6. — Section of Trail near Villa Farm, Tendring Hundred 

 Railway. 



.:vj>-.v ..■.;.-.:_; ->:?^ a. Warp. 

 :;V«/;^'?,.-:V:':'?:?:^;'f^'''.- b. Trail of sandy gravel. 

 ;;r^-.0;'i..-.'-V;-.v,\-v.:;T;-:3; <?• London clay, 



d. Weathered surface of 

 London clay, full of 

 Slickensides. 



I can cite instances which prove that considerable force has been 

 involved in this process. In a railway- cutting near Wivenhoe, 

 in Essex, I found at the side of a valley one of these farrows in 

 London clay, about 13 feet deep, filled with such sand and gravel as 

 caps the tableland around. The clay, for the thickness of 4 or 5 

 inches, was kneaded into a plastic state, laminated, and full through- 

 out of polished surfaces of slickensides, showing that the trail which 

 filled the furrow had been pushed forwards under great pressure, 



