122 Mr. J. S. Bowerbank on Carcharodon Megalodon. 



West Indian species, we shall find that the proportions of the teeth 

 of Carcharodon Megalodon are much more in accordance with 

 those of that shark than they are with the recent Carcharias. 

 Let us therefore see what dimensions will arise by comparison 

 of the fossil with the West Indian shark. Length of tooth of a 

 West Indian shark from the base line to the tip, ^ inch. The 

 vertical gape is 12 inches, or 13f lengths of the tooth. The 

 horizontal gape is 13| inches, or 15£ times the length of the 

 tooth. If therefore we take this species as the base of our cal- 

 culations in estimating the fossil one, the size will be very much 

 increased, and the following will be the result : — Length of fossil 

 tooth 4f inches. Vertical gape of jaw 13f times the length of 

 the tooth will equal 63| in., or 5 ft. 3f in. Horizontal gape of 

 jaw 15f times the length of the tooth will equal 72| in., or 

 6 ft. 0|^ in. Thus estimated the dimensions of Carcharodon will 

 be very considerably greater, and they will stand in comparison 

 with each other as follows : — 



Vertical gape by first estimate 3 ft. 11 in., by second 5 ft. 3f in. 

 Horizontal „ „ 3 ft. 2 in., „ „ 6 ft. 0| in. 



very nearly, by comparison with the West Indian species in- 

 stead of with the Australian one, doubling the dimensions of the 

 fossil fish : but probably the truth will lie in the mean between 

 the two estimates ; and this is the more probable, as we find great 

 latitude in size and proportions existing among the recent spe- 

 cies, which vary from the common dog-fish of our coast, about 

 2 feet in length, to the great basking shark, which Yarrell states 

 has been taken off Brighton 36 feet in length ; and the one 

 stranded in the Orkneys and described as a u sea serpent " is 

 said to have exceeded 50 feet in length. 



In conclusion, I may observe, that it is rather singular, that 

 although the teeth of Carcharodon are tolerably abundant in the 

 Crag, yet to the best of my knowledge no vertebrae have yet 

 been found in that formation of a size to correspond with them ; 

 while in the London clay, shark-vertebrae 4 inches in diameter 

 are found, without any teeth corresponding in dimensions to their 

 great size. If we had ever found teeth of Carcharodon of the size 

 of the Crag ones in the London clay, we might have reasonably 

 concluded that they had been washed out of that formation into 

 the Crag, as we know other well-known London-clay teeth as 

 well as Crustacea have been ; but under the present circumstances 

 it appears to me, that they have most probably found their way 

 into the Crag from the destruction of outlying portions of the 

 Maltese formation, in which they are found at the present period 

 in abundance; and this is the more probable, as they are associated 

 in the Crag with the teeth of a second Maltese shark, Oocyrrhina 



