Ball — On the Volcanoes and Hot Springs of India. 153 



iind that some of the sedimentary beds which often contain remains 

 of plants and animals (thus affording evidence of the age to which 

 they belong) have been baked by the superincumbent heated mass of 

 basalt, and have consequently received such names as porcellanic 

 shales and the like. Throughout these vast areas diligent research 

 has resulted in the discovery of no definite evidences of the former 

 existence of any volcanic cores or craters from whence these vast 

 masses of trap can have been poured forth. Nearer at home in the 

 north of Ireland, and in the west of Scotland, we meet with some- 

 what similar conditions, and, inferentially, it may be suggested that 

 wide-spread flows of trap will also be found to occur, or to have 

 formerly existed in the Soudan and other parts of Africa ; for, from 

 thence have been brought silicious pebbles similar in character with 

 those which are found in the other above-named regions, India has 

 long been renowned for the agates and carnelians, &c., which are 

 produced in the trap areas ; they have, when cut, been articles of 

 trade from the earliest times, the artificers having learnt how, by a 

 process of heating them in specially constructed ovens, to purify and 

 develop the beautiful combinations of colours which so far back as the 

 time of the Romans rendered the Murrhine vases famous and almost 

 priceless. 



Among traces of what has by some writers been supposed to have 

 been a volcanic centre is the Lonar Lake, a vast hollow in the trap in 

 Buldana District, Berar. But in the opinion of those most competent 

 to judge, it was more probably formed by an explosion which took 

 place long after the flows of basalt had been poured forth. Indeed it 

 affords an example comparable in its form and general characters to 

 the pipes and crater-like hollows which have proved so prolific a 

 source of diamonds in South Africa, the probable origin of which 

 has, I think, been very satisfactorily explained by Daubree's recent 

 experimental researches.^ 



The peculiar appearance of this Lonar Lake (of which I exhibit 

 an illustration) has given rise to much speculative imagination on the 

 part of the natives who, while regarding it as a sacred spot, also take 

 advantage of the benefits derivable from it as a source of certain 

 salts of some commercial value. The principal salt is the sodium 

 carbonate, which indeed is the most abundant salt in the trap regions 



^ Application de la Methode Experimentale au role possible des g;iz souterraines 

 dans I'Histoire des Montagnes Volcaniques. Extrait de I'Annuair' du Club Alpin 

 FrauQais, 18tli vol., 1891. Paris, 1892. 



E.T.A. PEOC, SEE. III., VOL. III. M 



