Geological Society. 297 



Franklin doubts whether it ever attains a thickness of 1 00 feet j 50 

 feet being perhaps a fair average. He never met with it in any other 

 situation than on the summit of the second range of hills. 



3. The overlying trap-rocks are not only the most extensive, but, 

 considering them in a geological view, the most important formation 

 in this part of India. The thickness of this formation is variable : 

 it reposes on every rock indiscriminately, from granite upwards j and 

 at Saugor it maybe seen on sandstone, where its inferior boundary is 

 about 1350 feet above the sea. In the centre of India it occupies the 

 summits of the highest mountains j and at Bombay it descends to the 

 level of the sea. 



There are two kinds of basaltic rock in the district of Jabalpoor, 

 clearly of distinct formations - } the older variety penetrates the grau- 

 wacke stratum, in the bed of Nermada river, near Lamaita ; the 

 younger is an overlying rock like that at Saugor, — but reposing on 

 granite, and containing a greater proportion of augite and olivine. 



Captain Franklin also describes a calcareous conglomerate, found 

 in the beds of most of the rivers whose sources or channels are in the 

 trap, and of sufficient cohesion for architectural purposes : its strati- 

 fication is always horizontal, and in point of age he thinks it must be 

 classed with the tufas and concretionary formations so prevalent in 

 India. 



An appendix to this paper contains the results of barometrical and 

 thermometrical observations made between Nov. 1826, and Feb. 

 1827, on the route from Mirzapoor to Saugor, and thence to Ten- 

 dukaira and Jabalpoor $ with the heights of fifty-four places above 

 the sea, and the latitudes and longitudes of the respective stations. 



An extract was read of a letter from Samuel Hobson, Esq. to Dr. 

 Roget, F.G.S. Sec. R.S. &c. (dated at New Orleans, 6th April, 1827,) 

 and enclosing an account of some gigantic bones, — by Samuel W. 

 Logan, M.D. 



The place where these bones had been found is not mentioned ; 

 but at the date of the letter, they were exhibited publicly at New 

 Orleans. Dr. Logan describes them as consisting of one of the bones 

 of the cranium, fifteen or twenty vertebrae, two entire ribs and a part 

 of a third, one thigh-bone, two bones of the leg,, and several large 

 masses of a cancellated structure. 



The cranial bone was twenty feet and some inches in its greatest 

 length, about four feet in extreme width (for the bone tapers to a 

 point), and it weighed twelve hundred pounds. Dr. Logan inclines 

 to think that this is the temporal bone. 



The vertebrae, consisting of a body, oblique transverse, and spinous 

 processes, gave sixteen inches as the mean diameter, and twelve 

 inches as the depth of the bodies j while the passage for the spinal 

 cord measured nine inches by six. The spinous processes stand 

 off backwards and downwards, fourteen inches in the dorsal, and 

 somewhat less in the lumbar vertebras, three of which latter are 

 entire. 



The ribs, well formed and in a perfect state of preservation, mea- 

 sured nine feet along the curve, and about three inches in thickness. 



New Series. Vol.4. No. 22. Nov. 1828. 2 Q The 



