1 70 6E0L0QY. 



SECTION IV. 



ADIORAT SANDSTO^XES. 



In the north-eastern portion of Tigrd, around Halai, 

 Senafd, and Adigrat, the rock resting immediately upon 

 the metamorphics is generally a massive sandstone. The 

 perpendicular scarps which usually bound the areas 

 formed of this rock, and flank all the valleys cut out 

 of it, are very conspicuous, from their height and their 

 white colour, and they give a very peculiar character to 

 the scenery. 



This sandstone — which, on account of its extensive 

 development around the important town of Adigrat, I 

 would propose to call the Adigrat sandstone — is usually 

 white or brown in colour, the former much predomi- 

 nating. Occasionally it is pale brown and lilac, or, as 

 about Takonda, brick red ; these colours being chiefly 

 restricted, however, to bands interstratified with the 

 mass of the rock. It is usually very quartzose, fre- 

 quently felspathic, less commonly argillaceous. Shales 

 of a blue or lilac colour are frequently met with towards 

 the base of the group, but the principal characteristic of 

 the great bulk of the sandstone is its massive character, 

 and the absence of marked bedding, so that the high 



