1840.] 



of the Great Basaltic District of India. 



99 



deposit*, it is necessary to mention that the}' are found in mountains in 

 great part composed of basalt resembling that of the Giant's Causeway, 

 but containing, more frequently, crystals of olivine, of basaltic horn- 

 blende, and carbonate of lime. This rock passes into a wacke, having 

 every variety of structure and induration knov/n amongst trap rocks, 

 or into what has been called stratified basalt, from the parallelism of its 

 planes, " the summits of many of the ravines presenting a continued 

 stratum for many thousand yardsf." 



Ascending from the Taptce river, Dr. Voyseyi observed a group of 

 basaltic columns, and near the summit of the flat table-land of Jillan, he 

 entered a pass presenting a perpendicular section, above the road, of 

 SO feet, and below it, a rapid descent of between 40 and 50. The lower 

 part of the section, as well as the pathway, is composed of wacke, and 

 " lying on it, is a stratum of earthy clay of different degrees of indura- 

 tion, 20 yards in length and about 2 feet thick, containing a great num- 

 ber of entire and broken shells," which are much compressed, and do 

 not effervesce with acids. Some of them completely commix with the 

 matrix. This bed of clay possesses all the characters of a stratum, 

 which Dr. Voysej- says, seems to have been depressed by an overlying 

 mass, 15 feet thick, of the nodular basalt or wacke so common in these 

 bills. The vertical fissures, which are so " remarkable in trap rocks, 

 are prolonged from both the upper and lower rocks, into the shelly 

 stratum, although there is no intermixture of substance." The stone in 

 which these fossils occur, is similar to that of Jirpah, and of many of 

 the specimens from the Sichel range and the valley of Berar ; and the 

 casts and fragments of the shells resemble those of the Paludinee and 

 other shells of that district. Between these mountains and the Sichel 

 hills, the great valley of Berar is included, but the two ranges closely 

 correspond in the nature of the soil and rocks, and in their fossiliferous 

 beds. They are not, however, exactly parallel ; nor do I think, that we 

 are justified in classing them with the Vindya range to the north of the 

 Nerbudda, or with the range which separates the valley of that river from 

 the valley of the Taptee. 



It is evident, from the same fossils being found in all these ranges, se- 

 veral hundred miles distant from each other, and from the same secon- 

 dary rocks being broken up and altered, that the basalt of which they 

 are principally composed was, in part at least, erupted at the same time ; 



* Geol. Tians., 2d Series, vol. iv., p. 426. 



+ Dr. Voysej', Asiatic Researches, vol. xviii,, p. 127. 



t Asiatic Researches, vol. xviii., p. 192, aud Journal of the Asiatic Society of Bengal, 

 vol. ii., p. 304. 



