£ 2 6 



PREHISTORIC EUROPE. 



caves. Now and again torrents flowing down the slopes of the 

 mountains swept the skeletons and carcasses of these animals 

 into gullies and underground galleries, where they gradually- 

 accumulated along with other superficial dSbris, and became in 

 time sealed up by the action of carbonated waters. Eventually, 

 however, a process of submergence ensued, and the land sank 

 into the sea to the depth of 700 feet or thereabout below its 

 present level. This movement seems to have been interrupted 

 by longer or shorter pauses, during which the sea cut terraces 

 or shelves upon the flanks of the Bock, shelves which have been 

 eroded partly in limestone and partly in the old limestone- 

 breccia (see Fig. 6, p. 217, and Fig. 10). By and by the sub- 



E. 



nkey'9 Cave Roa d 



Fig. 10.— Section showing relation of Upper Breccia to Raised Beaches— Gibraltar. 

 L, Limestone ; S 1 , Beach-deposits ; S 2 , Re-arranged beach-deposits ; B, Upper 

 breccia ; p 1 p\ Marine terraces. 



mergence ceased, and the land was again upheaved, probably in 

 as gradual a manner as it went down. The old sea-shelves were 

 then partially obscured by shelly sand and gravel which had 

 gathered over them ; and from the fact that the shells, so far as 

 can be made out, belong to species identical with those now 

 living in the neighbouring sea, we gather that the temperature 

 of the sea at least was at that distant date much the same as it 

 is to-day. To what extent the land was re-elevated we cannot 

 tell. It certainly attained a greater elevation than the present, 

 but whether or not Spain stretched as far to the south as it 



