90 GEOLOGY. 



springs of fresh water. In Spain there are salt hills 

 some hundreds of feet high. In Peru, salt is found 

 9,000 feet above the level of the sea. 



LIAS. This is a provincial name, and is given to this 

 group from its lying in layers. It is a marine formation, 

 and consists of argillaceous limestone, marl, and clay. 

 It extends from Whitby to Lyme Regis, in Somerset- 

 shire. These strata are said to be, in some places, 1000 

 feet thick. Various organic remains are found in these 

 strata, of which the Ammonite, the Gryphite, and the 

 Belemnite, are the most remarkable. 



In these strata are found the remains of that for- 

 midable animal, the Ichthyosaurus, which has nothing 

 resembling it in the present day. It had the head of 

 a lizard, with the teeth of a crocodile ; and was, in some 

 respects, like the porpoise. The expansion of its jaws 

 was tremendous : its eye was larger than a man's head, 

 and some Ichthyosauri exceeded 30 feet in length. It was 

 a marine animal. The Plesiosanrus was another animal 

 of asimilar kind, found in these strata. Its neck was of an 

 enormous length, like the body of a serpent, while its 

 trunk and tail had the proportions of an ordinary 

 quadruped. It had no feet, but paddles, like a whale, 

 and its long neck would have allowed it to breathe in 

 the air, while its body was concealed in the water ; or 

 have permitted it to seize on winged animals as it swam 

 along on the surface of a lake or sea. The remains of 

 animals of the crocodile kind are found in this forma- 

 tion, but, terrible as they are at the present day, they 

 sink into insignificance when compared with those of 

 the ancient world. 



OOLITE, or JURA LIMESTONE. The term Oolite is de- 

 rived from the Greek word oov, an egg, and is so applied 

 because many of the formations resemble, when examined 

 minutely, the roe of a fish. The Oolite is a marine for- 

 mation, and consists oflimestone, with beds of clay and 

 sandstone. Oolitic rocks are quarried near Bath, and 

 the stone is used for building. Coral rag, an oolitic for- 

 mation, is found near Oxford; and Portland stone, 

 also an oolitic formation, is found in the Isle of 

 Portland. These strata are about 1^00 feet thick. 

 There are various fossil plants and radiated animals 



