558. J. G. Malcolmson, Esq., on the Fossils of 



found in blocks of indurated clay, chert, and flinty slate. The appearance of the indurated clay 

 is the same as in some of the specimens from the Sichel Hills, but the clay is harder, full of cavi- 

 ties, and in some cases passes into perfect chert, or has waved lines of quartz or opalized matter 

 diffused through the substance of the mass. Many Physae, Paludinae, and a few Limneae of the 

 same species as those already noticed, are found in this indurated clay or imperfect chert. Some 

 of them are entirely converted into calcedony ; others have the lime replaced by quartz, which is 

 finely crystallized and covers the surface of the convolutions ; or the columella only is preserved, 

 passing across an empty cast of the shell. In some cases, however, the structure of the fossil is 

 unaltered, and it effervesces in acids. Flinty slate without organic remains occurs in the neigh- 

 bourhood of those amorphous masses, and many fragments of the same kind containing large com- 

 pressed bivalves are scattered about. In one block of this kind, portions of palm wood mineralized 

 by black flint, intersected by fine veins of a light blue opal, (of the same kind as occurs in some 

 of the specimens of fossil wood from Antigua, lately presented to the Society by Mr. Stokes,) was 

 found associated with compressed very thick bivalve shells, probably referable to the same species 

 as those of Munnoor. 



Every appearance presented by these rocks indicates the action of the semi- 

 fluid basalt on the beds of mud and sand, probably derived from the neigh- 

 bouring sandstones and schists, in vs^hich the shells previously existed. 



At Hingan-ghat*, a few miles further to the north, considerable fragments 

 of silicified palms and other plants w^ere found in a black chert lying on the 

 basalt, and similar masses, but without fossils, were imbedded in it. I met with 

 no organic remains to the north of this town, the whole country as far as the 

 city of Nagpoor being covered with a rich black soil, from which insulated 

 basaltic hills with flattened summits rise abruptly. 



Of these hills the most remarkable is that of Seetabuldee, which is based on 

 decomposing gneiss and mica slate. To Dr. Voysey's description! I have no- 

 thing to add ; but as it has been inferred J, that the " flattened summits and 

 long flat outline" of the low ranges connected with this celebrated hill, and 

 forming the eastern part of the great trap district, are composed of basalt 



* In examining with the microscope sections of some of the silicified wood from the district de- 

 scribed, a specimen from the chert of Hingan-ghat appeared to me to be bone, and Mr. Owen, 

 who has had the kindness to examine it, has ascertained it to belong to a mammiferous animal. 

 He has favoured me with the following note on this important fossil : 



" A section of this fossil was prepared sufficiently thin to allow of its being examined by trans- 

 mitted light under a high magnifying power, when it was found to possess the structure charac- 

 teristic of bone. Sections of ' Haversian canals,' with their concentric lines, were everywhere 

 present, interspersed with numerous Purkingian cells or corpuscles : the size and disposition of 

 these characteristic parts of the osseous structure agreed with those of the bones of the Mam- 

 malia. It was highly satisfactory to find the microscopic test as available in demonstrating the 

 presence of bone, when ordinary characters and the unassisted eye would have left the matter 

 doubtful, as it is in reference to the determination of the teeth." — July, 1839. 



f Asiatic Researches, vol. xviii. J Geological Transactions, Second Series, vol. 4th, p. 410. 



