4 TRAPS AND INTERTRAPPEAN BEDS 



species of freshwater shells mentioned by Mr. Hislop, as obtained by him 

 from Rajamundry, but I met with a well preserved specimen which I have 

 little hesitation in referring to, Lymnea suhulata. SoWj a shell as charac- 

 teristic of the Central India inter trappeans as Physa Frinsepii is. I can 

 therefore to some extent confirm Mr. Hislop''s deductions as to the exist- 

 ence of traps belonging to the Deccan series at Rajamundry, but I do not 

 think it is yet satisfactorily shown that these rocks ever extended across 

 the intervening area, although I by no means think such a former exten- 

 sion improbable. Outliers are represented on Malcolmson's map, already 

 referred to, as dotted over much of the intermediate country, but of 

 these, one of the largest is represented as stretching for a considerable 

 distance along the Godaveiy at Bhadrachellum, which town appears in 

 the map to stand upon the outlier. In a recent journey down the Godavery, 

 which, however, was too hurried to allow me to search to any extent, I 

 did not observe any of these outliers, and at Bhadrachellum all the rocks 

 appeared to be metamorphic ; but my means of observing were far from 

 sufficient to enable me to state that trap does not occur in the neigh- 

 bourhood of the river. Other outliers of basalt appear marked on the 

 same map near Ongole, 150 miles south-west of Rajamundry, and about 

 the same distance south-east of Hyderabad. I do not know to what 

 formation these belong. 



Some observers have considered the trap dykes which occur in 

 metamorphic and other rocks throughout India evidence of the former 

 extension of the Deccan trap. This, however, is an error, as has been 

 shown by Newbold and others, there being abundant evidence that these 

 dykes are, in many instances, of far greater antiquity. 



To the west I can add something more positive as to the extension 

 of the trap area. I have shown in a previous paper* in this volume that 



* See ante, p. (21). 

 ( 140 ) 



