180 WYNNE : GEOLOGY OE KllTCH. [PART It. 



Joondia hill, though smaller, presents a precipitous face to the north, ex- 

 posing white gritty and felspathic sandstone. 



Columnar sandstone. n , • i 



parts of which are columnar in regular hexagonal 



prisms.* 



A large trap dyke cuts through the hill, altering the adjacent rocks, 



and underneath the columnar sandstone some decayed trap appears to 



have been intruded, the bed beneath which is so highly altered as to 



have become a kind of hornstono. 



That portion of the trap escarpment south of the Katrol range 



Escarpment ot the forms a well-marked feature when seen from a 



laps. distance, the unconformity to the jurassics being 



apparent, while on detailed examination the junction is found to be much 



overrun with local debris and sub-recent calcare- 



Calcareous concrete. 



ous concrete, which also occurs at higher eleva- 

 tions near Keroee and other places. It is largely burned for lime. 



In this neighbourhood the traps have a south-easterly dip and 

 present alternations of concretionary solid and decomposed basaltic 

 flows, with fine examples of columnar structure in the gorge of the 

 Keroee stream. 



Katrol Hill gives its name to a portion of the range, has an eleva- 

 tion of about 550 feet above the plain to the 

 Katrol Hill. 



north, and is the most lofty summit of the whole 



chain, the steep northern escarpment of which is very persistent to, the 

 west, though the heights gradually decline. Between the scarp and 

 the plain to the north are some low hills which, west of Lair, form a 

 subordinate parallel ridge. The principal range, like most of the 

 others in Kutch, coincides with an anficliual curvature of the beds. 



* This occurs so frequently in the upper jiirassio area as to suggest the posaihility of 

 its having formed the floor of a trappeau flow, and it may here indicate a small outlier of 

 the upper portion of the Jurassic heds. 



( ISO ) 



