Chap. 1.] economic geology. 217 



Throughout the trap country limestone is in general wanting, except 



where beds of calcareous intertrappeans occur. These 

 Trap country. 



are only found near the base, and are in general 



wanting to the westward. A bed near Burwai afforded the best limestone 

 for iron smelting that could be found in the neighbourhood. With this 

 exception the only source of lime in the trap country is the kunkur, 

 which abounds wherever there is a deep soil above the rocks, and especi- 

 ally in the larger masses of alluvial clay. 



The nummulitic limestone affords excellent lime, and might, if a 



little less distant, be available for he supply of 

 Ntunmulitics. t> , , ,. . 



Bombay, where lime is greatly needed. It occurs 



in great quantities around Turkesur, near Surat. 



Slate. — It is very difficult to judge of the quality of slate by what 



is seen at the surface, unless a very good section is exposed in a hill side, 



and this is not the case in the slates which occur between Soorajpoor and 



Jumbooghora, north-east of Baroda. So far as 

 Near Baroda. • ^^ -, 



they are visible at the surface, however, they are 



promising. There are also some slates seen in the Bijawur beds, near 



Bagh, which might be available for many purposes, 



and some of which might perhaps be sufficiently 



homogeneous to be used for roofing, but they are less fine grained than 



those of the Champaneer beds. 



Building Stones. — These abound. Many of the trap beds furnish 



admirable building stone, extremely tough, yet 

 Trap. 



not excessively hard, quite free from joints and not 



liable to injury by exposure. At the same time some caution is necessary 



in selecting basaltic rocks for building purposes. None of the beds 



containing zeolites interspersed in irregular strings and veins throughout 



the mass are good. They are soft, brittle and liable to decompose. None 



of the ash beds are equal in strength, toughness, or resistance to the 



atmosphere, to the soUd basalts, and no rock of a red colour should 



ever be taken for building purposes. It is almost always decomposed. 



D 1 ( 379 ) 



