the Eastern Portion of the Basaltic District of India. 571 



this lofty basaltic range, Dr. Voysey discovered fossil shells, the situation of which he has accu- 

 rately described * ; but as his account of them, has been so far misunderstood, as to induce Mr. 

 Conybeare to state that they occur in " lias-like bedsf," and Colonel Sykes in a recent deposit t, 

 it is necessary to mention that they 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 hornblende, and carbonate of lime. This rock passes into a wacke, having every va- 

 riety of structure and induration known amongst trap rocks, or into what has been called stra- 

 tified basalt, from the parallelism of its planes, " the summits of many of the ravines presenting a 

 continued stratum for many thousand yards §." 



Ascending from the Taptee river. Dr. Voysey !| observed a group of basaltic columns, and 

 near the summit of the flat table-land of Jillan, he entered a pass presenting a perpendicular sec- 

 tion, above the road, of 30 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 induration, 20 yards in length and about 2 feet thick, containing 

 a great number 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. Voysey says, seems to have been depressed by an over- 

 lying mass, 15 feet thick, of the nodular basalt or wacke so common in these hills. The vertical 

 fissures, which are so " remarkable in trap rocks, are prolonged from both the upper and lower 

 rocks, into the shelly stratum, althougli 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 tlie shells resemble those 

 of the Paludinae 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, several 

 hundred miles distant from each other, and from the same secondary rocks 

 being broken up and altered, that the basalt of w^hich they are principally com- 

 posed was, in part at least, erupted at the same time ; and that the western 

 and eastern ghats must have partaken in this great movement. 



Shells, probably of the same genera, were also found by Dr. Voysey in the insulated basaltic 

 hills of Medcondah^ and Sivalingapah, which rest on the granite of the Deckan, south of theGo- 

 davery, and are probably connected with the southern part of the great trap district, and the hills 

 of Bicknor Pett and Nugger shown in Section 1., PI. XL VI. The fossils are imbedded in the 

 basalt, in a siliceous rock containing lime, and corresponding in specific gravity, chemical com- 



* Asiatic Researches, vol. xviii., p. 187. t Report to the British Association, 1832. 



X Geol. Trans., 2nd Series, vol. iv., p. 426. § Dr. Voysey, Asiatic Res., vol. xviii., p. 127. 



II Asiatic Researches, vol. xviii., p. 192, and Journal of the Asiatic Society of Bengal, vol. ii., 

 p. 304. 



^ In a specimen of this chert in the Geological Society's Museum, I have found a gyrogonitc of 

 the same kind as those of Nirmul, and halves of a species of Cypris associated with shells. June 

 24,1839. 



VOL. V. SECOND SERIES. 4 E 



