AN ANCIENT PORTLAND INTERMENT. 233 



very ancient interment. Fissures are not uncommon in the island ; 

 varying from one foot to several feet, and are for the most part 

 widest at the bottom, narrowing as they approach the surface. 

 Human remains have been found in other fissures of the island 

 associated wih the bones of large animals mammoth, deer, wild- 

 boar, ox, &c. neither water worn, nor showing signs of attrition. 

 Similar bones may be seen in the cases of the Royal Engineers' 

 office from the quarries on the Verne. The strata in connection 

 with the fissure and through which it passes are the cap, skull-cap, 

 and the intermediate dirt-bed, the lowest members of the Purbeck 

 series. Here they are six feet thick and are succeeded by the 

 Roach-bed, which is three feet and a-half thick ; this bed is 

 composed of various shells, of which only the casts remain. Its 

 characteristic fossil is Cerithium portlandicum, locally called the 

 " screw." So abundant is it that the smallest chip contains some 

 portions of it. In some parts of the island the Roach consists 

 almost entirely of Plicatula and Lithodomi. At the "Bill" oysters 

 predominate. The lowest beds are interspersed with chert and 

 flint, either in layers or in nodules. The next succeeding bed of 

 the Portland series is the Whit-bed, the most valuable stone of 

 the island, varying from a close-grained to an oolitic structure, 

 differing in various parts of the island, both in quality and compo- 

 sition. Sometimes it is intercalated with siliceous seams, or bars, 

 as they are locally called. The most common shell is Perna 

 mytiloides and Pecten lamellosus. When composed of oolitic 

 grains it is of a brownish-buff colour ; it is found in this form in 

 the northern part of the island and considered to be the best 

 building stone. The presence of shells makes it susceptible to the 

 disintegrating action of the atmosphere, by which the lime is 

 dissolved, leaving the shells to stand out in relief. I shall not 

 trace the series further downwards, as the next succeeding bed 

 the Curf has no connection with the bones. The island has 

 undergone great changes since the deposition of even the most 

 recent beds, chiefly from the effects both of elevation depres- 

 sion and denudation. There is abundant evidence that the Middle 



