56 



GEOLOGY. 



The Flying Lizards of the Chalk and Greensand, however, 

 attained a far larger size — but their remains are all very frag- 

 mentary. For example, some detached vertebrae of the neck of 

 one species have been found in the Cambridge Greensand, measuring 

 2 inches in length, and portions of humeri 3 inches broad. Such bones 

 give evidence of a flying lizard having probably an expanse of wings 

 of from 18 to 20 feet. The Pterodactyles of the Chalk of Kent were 

 nearly if not quite as large. These singular flying reptiles do not 

 appear to have lived longer than the period of time represented by the 

 deposition of the strata from the Lias formation to the Chalk. They 

 are now entirely extinct. 



In this case (1) are also placed the remains of the great aquatic 

 Lizard-like reptile which once inhabited the shores of the sea in 

 which the Uppermost Chalk, or Maestricht beds were deposited, 

 and known as the Mosasaurm, whose powerful jaws, armed with 

 great grooved, recurved, conical teeth, have been obtained from St. 

 Peter's Mount, near Maestricht, and (under the name of Leiodon) 

 from the Chalk of Norfolk and Kent. Kemains of over forty species 

 of this tribe have been found in the Cretaceous rocks of New Jersey, 



B A 



Fig. 26.— a, The Skull, and b, Tail-sheath, of the great Horned Lizard {Megalania prisca, 

 Owen), from the Newer Tertiary deposits of Australia. 



Kansas, &c, in North America. One of these, the Mosasaurus prin- 

 cess, is computed to have been 75 to 80 feet long. The body was 

 covered with small overlapping bony plates. The paddles, which were 

 four in number, each with five digits, had a remarkable resemblance 

 to the " flippers " of a whale. 



Here are also placed the remains of a great extinct land-lizard 

 {Megalania prisca, Owen) from Australia, 14 feet, or even more, 

 in length, with nine horn-like prominences on its skull, which 

 measured 1 foot 10^ inches in breadth. The skull, at first glance, 

 looks like that of some flat-headed form of Ox ; but the bones are 

 altogether dissimilar, and the jaws are without teeth. It was prob- 

 ably a vegetable-feeder, like its pigmy living representative (Mo/och 

 horridus), also from Australia, which has horny prominences on its 

 skull, but the entire length of this little lizard is only 7 inches. 



Since the two papers by Professor Owen (Phil. Trans, for 1858 

 and 1880) on this curious and huge lizard have appeared, a further 

 portion of its remains have been sent over, showing that it possessed 

 a tail encased in a horny sheath (see Fig. 26, b), so like the 



