CH. I. CHANGES OF SEA LEVEL. 23 



worked for the same purpose, tbe process is sure to be 

 continued. In connection with the question raised of late 

 years as to change of relative level of land and sea within 

 the historic period, we observed some very ancient mark- 

 ings that showed the works to have been carried somewhat 

 below the present level of high tide ; but we could trace 

 none that appeared to reach so low as that of the ebb tide. 



So far as the eviderce at this point goes, it seems to 

 prove a slight amount of submergence during the period 

 for which the rock has here been quarried. This period 

 may probably be reckoned at 2,000 years, and possibly 

 much exceeds that limit. Taken in connection with still 

 existing remains in Greece, Asia Minor, the Phoenician 

 coast of Syria, and Egypt, it tends to show that the 

 changes in the general level of the Mediterranean coasts, 

 indicated by many geologists, must have proceeded very 

 slowly during the historic period, and that the more con- 

 siderable oscillations, that have undoubtedly occurred near 

 Naples and on the east coast of Sicily, have been mainly 

 due to the local influence of volcanic action. 



The soil near the cave was much mixed with sand car- 

 ried by the wind, and the plants seen were chiefly widely 

 diffused species that find tolerably uniform conditions of 

 life on the sandy shores of the west coast of Europe. The 

 rocks near the cave produce samphire and the sea fern 

 (Aspleni')i.m marinuTn), just as they do in Cornwall ; 

 while Diotis maritima and Lotus Salzmanni, a local 

 variety of the widely spread Lotus creticus of Linnteus, 

 were frequent on the sands. The chief ornament was 

 Statice sinuata, whose delicate azure flowers were already 

 in blossom, long before most of the species of that late- 

 flowering genus. 



Our course now lay inland ; but, instead of following 

 the direct way back to Tangier, we were led by a false 

 report (our first experience of blundering interpretation 

 of English by the help of Moorish Arabic) to bear to the 

 left, and recross the Djebel Kebir, so as to take Sir J. T>. 



