SECTION VI. 



TRAPPEAN SERIES. 



The greater portion of the Abyssinian plateau, with 

 the exception of its north-eastern corner, is known to be 

 covered by volcanic rocks. Much has yet to be done 

 before their geology can be properly ascertaiaed. No 

 opportunity was afforded during the expedition of visit- 

 ing the remarkable trachytic ranges around Adowa, and 

 it can only be inferred from the form of the hills that the 

 rocks are similar to those of Senafd. Far to the south in 

 Shoa the trap rocks, as described by M. Eocher d'Heri- 

 court,^ appear to correspond with those of the neigh- 

 bourhood of Magdala. From the accounts given by 

 Messrs. Ferret and Galinier, Dr. Rtippell, and others, it is 

 evident that the high mountains of Simen and the whole 

 country around Lake Dembea consist of the same bedded 

 traps. By the kindness of Dr. Beke I have been allowed 

 to examine a series of specimens collected during his 

 journeys in Central Abyssinia, which entirely confirm 

 these accounts, and prove that the rocks of the hills on 

 the banks of the Abai, and those both north and south of 

 Lake Dembea, are precisely similar to the traps of Lasta, 



1 Bull, de la Soc. G^ol. de France, 1846, p. 543. 



