152 Geological Society : — 



In the semi-major axis the greatest departure from the average 

 is 285 feet (in the Russian are) ; in the semi-minor axis the 

 greatest departure is 62 feet (in the Anglo-Gallic). These near 

 coincidences of the Three Long Arcs show how well their ave- 

 rage ellipse represents the mean ellipse. I take, therefore, as 

 stated in my first paragraph, the semiaxes of the mean ellipse to be 



0=20926184, and 6 = 20855304. 



5. These values which I give for the mean semiaxes differ by 

 only 164 and 71 feet, the first in defect and the second in excess, 

 from the values assigned in the British Ordnance Survey Volume. 

 But this near coincidence arises simply from the fortuitous cir- 

 cumstance that the algebraical sum of the local attractions 

 throughout each of the Great Arcs, viz. (/,), (t 2 ), (t 3 ) , is a minute 

 quantity. Had this not been the case, the calculation in the 

 Chapter on the Eigure of the Earth in that volume would not 

 have been so near the truth, as unknown local attraction is not 

 there taken into account. 



Calcutta, November 22, 1866. 



XXI. Proceedings of Learned Societies, 



GEOLOGICAL SOCIETY. 



[Continued from p. 7b.~] 



December 19, 1866.— Warington W. Smyth, Esq., M.A., F.R.S., 

 President, in the Chair. 



THE following communications were read : — 

 I. " On anew specimen of Telerpeton Elginense" By Prof. 

 T. H. Huxley, LL.D., F.R.S., V.P.G.S. 



The specimen which was described in this paper had been broken 

 into five pieces, exhibiting hollow casts of most of the bones of 

 Telerpeton Elginense. It is the property of Mr. James Grant of 

 Lossiemouth, and came from the reptiliferous beds of that locality, 

 along with some highly interesting fragments of Stagonolepis and 

 Hyperodapedon. The casts described by the author consisted of 

 impressions of the bones of the skull, together with the lower jaw, 

 and the teeth, of most of the vertebrae and ribs, of the greater 

 portions of the pelvic and scapular arches, and of representatives of 

 most of the bones of the fore and hind limbs ; and it was stated that 

 the characters of all these portions of the skeleton indicated deci- 

 dedly Lacertilian affinities. 



In describing these remains, Professor Huxley discussed especially 

 the biconcave character of the vertebrae, the mode of implantation 

 of the teeth (which he believed to beAcrodont, and not Thecodont), 

 and the anomalous structure of the fifth digit of the hind foot (which 



