182 GEOLOGY. 



On the route to Magclala volcanic rocks were first met 

 ■with at Senafe, where several hills consist of trachyte 

 passing into claystone and basalt. Trap hUls, chiefly of 

 trachyte, are dotted over the country to the southward as 

 far as Fokada, a distance of nearly thirty miles. Here a 

 great range of bedded traps commences, and extends for 

 about twenty-five mUes to the south, passing to the west 

 of Adigrat. From a little south of that town no volcanic 

 rocks were met with, except the beds mentioned in the 

 last section as occurring interstratified with the Antalo 

 limestones, until some distance south of Antalo ; but at 

 Meshek, two marches beyond that town, the route entered 

 high ranges entirely composed of trap, and thence no 

 other rocks were seen as far as Magdala. 



In the Meshek valley and in other valleys to the 

 south, especially at Atala, Aiba, and Belago, it is very 

 plainly seen that the trappean rocks belong to two dis- 

 tinct and unconformable groups. The lower of these is 

 much inclined, while the higher rests on its upturned and 

 denuded edges. In this part of the country the two 

 groups are easily distinguished by the absence of dis- 

 turbance in the higher beds. Nothing can be more 

 complete than the evidence of unconformity. Of these 

 two groups the lower or inclined beds may, for the sake 

 of distinction, be called the Ashangi group, from their 

 development around the lake of that name, and the 

 higher or horizontal beds the Magdala group. They are 

 evidently of different geological age, and require separate 

 description. 



