MONOGRAPH 



ON THE 



FOSSIL REPTILIA OF THE LONDON CLAY. 



YOL. II. 



RESTORATION OF CHELONE GIG AS, Ow, A SPECIES INDICATED BY A 

 FRAGMENT OF THE FEMUR IN A FORMER MONOGRAPH. 1 



In the ' Monograph on the Fossil Reptilia of the London Clay, Supplement to the 

 Order Chelonia,' 1 the proximal end of the femur of a very large marine Chelonian is 

 noticed and figured in PI. XXIX, fig. 5, and the size of the species in proportion to the 

 largest known existing Turtle, an individual of Chelone mydas, which weighed 150 lbs., 

 is illustrated by a subjoined figure of the entire femur of that individual (fig. 5'). The 

 breadth of the proximal end of this femur across the trochanters is barely two inches, the 

 same dimension of the fossil is four inches ten lines. 



In 1858 the British Museum obtained the upper portion of the cranium of a Chelone 

 from the same formation and locality (Sheppey), corresponding in magnitude with the 

 above-cited portion of fossil femur, and it was registered and labelled as of the Chelone 

 ffigas? 



In the present year, 1879, W. H. Shrubsole, Esq., F.G.S., submitted to my exami- 

 nation an almost entire cranium and other portions of the skeleton of the same gigantic 

 species of Turtle, which had been exhumed fronTthe septarian modification of the London 

 Clay at Sheppey. The following are dimensions of the fossil (PI. I) and of the largest 

 cranium of Chelone mydas in the Zoological Department of the British Museum. 



1 Palaeontographical Society's Volume, issued for the year 1849, 4to., PI. XXIX, fig. 5, 1850. 



2 ' Palaeontology,' 8vo., 2nd ed., 1861, p. 317. 



1 



