FOSSILS AND THEIR STORY 



109T 



HOPLITES LAUTUS—A FOSSIL NAUTILUS 

 FROM THE GAULT. 



glades. and were captured in the 

 snares of strange spiders ; while scor- 

 pions, centipedes, and leaf-insects 

 crawled amongst the rank vegetation. 

 Indeed, the Coal measures and Car- 

 boniferous Limestones abound with 

 fossil remains, the oval nodules of 

 hard clay which are found in the 

 coal seams }ielding a rich harvest of 

 fossils. 



The next most interesting formation 

 to the amateur geologist is the Lias, which 

 has yielded an enormous number of most 

 important fossil remains, all in a wonder- 

 fully perfect state of preservation. It 

 was an age of gigantic aquatic reptiles, 

 the Ichthyosaurus and Plesi- 

 osaurus. creatures measuring 

 from eighteen feet to thirty 

 feet in length ; of wonderful 

 fishes, and countless mollusca. 

 The ancestors of the modern 

 Cuttle-fish and Octopus were 

 exceedingly numerous, and 

 their well-preserved fossil re- 

 mains abound, more than 130 

 species of .\mmonites and nine 

 species of Nautilus having been 

 found ; indeed, the different 

 zones of the Lias are character- 

 ised by particular Ammonites. 

 Vast numbers of a species of 

 oyster or Gryph?ea are found 

 in the Lower Lias, which is 

 sometimes in consequence 

 called rjryi)hite Limestone. 



The Oolite and Purbeck beds 

 afford a large number of most 

 interesting fossils, for in the 



latter formation have been found the 

 fossil remains of several species of warm- 

 blooded marsu])ials. The plants of the 

 Purbeck beds consist chiefly of ferns, 

 conifers, and cycads, and all point to a 

 tropical or semi-tropical climate, for the 

 Araucarian pines which are now living 

 in Austraha and its islands, together with 

 marsupial quadrupeds, are found in the 

 same way to have accompanied the 

 marsupials in Europe during the Oolitic 

 period. The OoHtes yield beautiful 

 examples of the fossil " Stone Lilies " or 

 Crinoids, which arc not plants, but related 

 to the Star-fishes. They are of very great 

 interest, not only on account of their 

 beauty, but also from the fact that though 

 so numerous in past geological ages, the 

 genera have gradually dwindled, until but 

 a few members of this ancient family, 

 hke Pentacrinus and Comatula, survive 

 in the seas of to-day. 



The Upper and Lower Cretaceous, or 

 chalk formations, include many remark- 

 able fossil remains. The earhest fishes 

 with internal bony skeletons occur in 

 Cretaceous rocks, together with the 

 Iguanodon, a gigantic reptile that walked 

 on its hind legs, and the strange Ptero- 

 dactylus, or Winged Lizard, which 

 measured sixteen feet six inches from tip 

 to tip of its outstretched wings. 



F. Martin' Dunxax. 



ENCRINITIC LIMKSTONE COMPOSED OF THE STEMS OF 

 STONE LILIES (ENCKINITES). 



