GEOLOGICAL NOTES ON THE ISLE OF PORTLAND. 63 



loam, became suddenly entombed and carried down to the lowest 

 levels. Among the debris are fragments of the middle Pur- 

 becks which do not now exist in situ in the island. It is angular 

 or sub-angular, and intercalated with seams of loam show- 

 ing traces of rough stratification. Professor Prestwich met 

 with another mass of rubble and loam above Chesilton. It 

 forms a low cliff 60 feet in height and composed of angular 

 debris of the Purbeck beds and Po rtland Stone, interstratified 

 with irregular beds of loam. The mass contained a few land 

 and freshwater shells, also two Ostracode Crustaceans, 

 Crypris and Candona. The angular debris extends 

 to a height of almost 200 feet and is distinct from 

 the talus occasioned by the tear and wear of the existing Cliff 

 above.* 



I now come to another deposit of an age long anterior to the 

 above ; occupying a very restricted area, a little to the south of 

 the Verne, and about 400 feet above the sea-level. 

 It is a drift-bed of great antiquity, consisting of a 

 red-clay or loam passing into a coarse loess and in some places full 

 of angular local debris of the Purbeck beds and Portland stone, 

 with a considerable number of small blocks of Sarsen stone of the 

 Lower Tertiaries, much worn and stained, underlain here 

 and there by a singular layer of pebbles, waterworn and per- 

 fectly rounded, in a mixture of sand and red-loam with 

 a large proportion of peroxide of manganese ; the pebbles were 

 clean and bright, as if they had been artificially polished. The 

 material was derived from the Tertiary, Chalk, Upper Green sand> 

 and Portland beds, and possibly from some old Gravels. In tha 

 lowest part of the deposit were the foil owing mammalian remains, 

 a molar of Elephas antiquus, fragments apparently of a large 

 molar of Elephas primigenius ? Equus fossilis E. spdiceus ? 

 Bos and Cerviis. When the deposit was first discovered it con- 

 tained a large number of teeth of elephants, but only a few of 

 these were preserved by tha Go vernor of the Prison, Captain 



* " Quarterly Journal of the Geological Society, 1875," 



