296 JOSEPH PRESTWICH, F.E.S._, F.G.S., ON A POSSIBLE 



In this pit, moreover, there are flint and chert implements of 

 two or three periods. Few of them are possible valley types. 

 There are (1) the plateau types, showing the -usaal wear; 

 (2) high-level types, very few of which show any vrear, but are 

 sharp and unstained.* These implements occur, accoixling to the 

 qnarrymen, at no particular horizon, and at no particular spot, 

 but at all levels. They are mostly of chert. Tiie depth of the 

 section at iis highest point was about 50 feet. 



De la Beche described a mass of detritus close to Waddon 

 Barton near Chudleigh, Devoir. f He inclined to the opinion that 

 it was suddenly accumulated by a wash of waters over the Haldon 

 Hills. The accumulation occurs on a small limestone hill. 



Dr. Prestwich's theory of submergence and sudden elevation 

 in a series of uplifts gives the necessa/ry explanation of the 

 phenomena at Waddon Barton, at Broom Ballast Hole, at two 

 other ballast pits between Broom and Axminster, and at many 

 other places where similar conditions exist. There is evidence in 

 these and similar cases of sudden water transport which carried 

 older and newer gravels down the slopes whereon they reposed, 

 and angtdar and subangidar debris of the local rocks which is the inland 

 representative of the Head or Babble Drift overlying the raised beaches. 

 This angular debris is very important as it is conidusive that we are 

 not dealing with an ordinary river gravel. The rolled pebbles 

 and the stained and worn implements from the highest levels and 

 the ^minjured high-level implemerds mixed with sand and clay and 

 angular and subangular debris, is all evidence that v/e are not 

 dealing with an ordinary but an extraordinary accumulation of 

 material derived by sudden action from higher ground. 



Sliding down an easy slope such as the hills bordering the Axe 

 valley exhibit, borne by strong effluent currents such as Dr. 

 Prestwich posits as the vera causa, the unstained and unrolled 

 high-level implements have reached their present positions intact. 



With regard to the Ossiferous Fissures near Plymouth some 

 belong to the period postulated, and some possibly not. J 



There are important fissui-es at Oreston systematically examined 

 by Whidby, Buckland, and others. I visited the spot last 

 Janaary. The bones of extinct mammalia in this case occurred 

 pellmell, separately and unconnected with each other, amid 

 angular masses of limestone. They were not the bones of com- 



* See also D' Urban on Broom Pit, Geological Magazine, ISVS, p. 37. 



+ Geology of Cormcall and Devon (1839), p. 410. 



X The Cattedown tissure in whicb remains of iifteen human skeletons 

 was found does not rest on sutRciently disciiniinating evidence. An 

 oyster shell occui'ied in this fissure and is pieserved in the Plymouth 

 Athenaeum. But the final catastrophe, judging from the character of the 

 cave and the nearness to sea-level, may have been caused by a tidal wave 

 entering Plynioiith Sound. See E. N. Worth, Transactions Devon Aiso- 

 ciaiion, 1878, p. 429. 



