ADK\ SERIES OF rOLCANIC ROCKS 191 



iuterstratified" with which are sedimentary rocks, sand- 

 stones, and conglomerates. 



As a rule these beds are inclined, and present the 

 appearance of having been much disturbed. The beds 

 of the Buri peninsula were only examined in one spot. 

 Those of the neighbourhood of Zulla are most irregular 

 in dip, whilst in the tract west and north-west of Mas- 

 .sowa, with some irregularity, there is a very constant 

 general dip towards the sea to the eastward. 



The sedimentary beds contain a mixture of sand, ashes, 

 and rolled fragments of both volcanic and metamorphic 

 rocks. Fossil shells are said to occur in places ; unfor- 

 tunately nothing was met with except some fragments 

 insufficient for determination. 



At the south end of Annesley Bay, just south of the 

 Turkish port at Arafile, there is a cone composed of fine 

 volcanic ash. From its form this cone is evidently of 

 recent origin. About two days' journey to the south 

 there is said to be an active volcano. 



Although there can be but little doubt of the recent 

 date of a large portion of this series, the great amount of 

 denudation which parts of it have undergone around 

 Zulla and Massowa,^ where no trace of the original 

 volcanic vents can be detected, and the very considerable 

 disturbance which has affected the beds, prove that some 

 portions of the series are of ancient date, and that 

 the geological period during which they have accumu- 

 lated must have been of long duration. It is unfortu- 

 nate that no good specimens of the fossil shells occur- 



' The same is the case at Aden. 



