194 GEOLOGY. 



SECTION VIII. 



RECENT FORMATIONS. 



Alluvial Deposits near the Coast. — The plain around 

 ZuUa consists of alluvium, doubtless deposited by tbe 

 Haddas and Komayli streams. It extends to the Gadam 

 hUls and to the spiir of volcanic rocks stretching away 

 from the south end of the range. Beyond this spur 

 another plain, which is continuous with that along the 

 seashore to the southward, extends to the foot of the 

 mountains at Wia Hadoda and Komayh. This plain 

 consists of beds of sand and gravel, evidently deposited 

 by streams from the hills. At the entrance to each 

 ravine the plain is raised considerably by the accumu- 

 lation of detritus brought down by the torrents. 



The spurs of the Gadam range almost reach the sea, 

 an exceedingly narrow plain intervening. This plain is 

 almost equally narrow near Arkiko. The island of Mas- 

 sowa and the coast, for some distance at least to the 

 northward, are of coral formation. Northwards from 

 Massowa, however, the country for many mUes from 

 the sea is covered by an accumulation of pebbles and 

 boulders of metamorphic rocks and trap. In places, as 

 near Amba, about thirty miles north-north-west of Mas- 

 sowa, these beds form flat-topped rises of no great height, 



