THE JURASSIC PERIOD. 255 



Jurassic fauna of Western Europe approached to that now 

 inhabiting Australia. At the present day, Australia is almost 

 wholly tenanted by Marsupials ; upon its land-surface flourish 

 AraucaricK and Cycadaceous plants, and in its seas swims the 

 Port-Jackson Shark ( Cestracion Philippi} >; whilst the Mollus- 

 can genus Trigonia is nowadays exclusively confined to the 

 Australian coasts. In England, at the time of the deposition 

 of the Jurassic rocks, we must have had a fauna and flora very 

 closely- resembling what we now see in Australia. The small 

 Marsupials, Amphitherium, Phascolotheriiun, and others, prove 

 that the Mammals were the same in order ; cones of Arau- 

 carian pines, with tree-ferns and fronds of Cycads, occur 

 throughout the Oolitic series; spine-bearing fishes, like the 

 Port-Jackson Shark, are abundantly represented by genera 

 such as Acrodus and Strophodus ; and lastly, the genus Tri- 

 gonia, now exclusively Australian, is represented in the Oolites 

 by species which differ little from those now existing. More- 

 over, the discovery during recent years of the singular Mud-fish, 

 the Ceralodus Fosteri, in the rivers of Queensland, has added 

 another and a very striking point of resemblance to those 

 already mentioned ; since this genus of Fishes, though pre- 

 eminently Triassic, nevertheless extended its range into the 

 Jurassic. Upon the whole, therefore, there is reason to con- 

 clude that Australia has undergone since the close of the 

 Jurassic period fewer changes and vicissitudes than any other 

 known region of the globe ; and that this wonderful continent 

 has therefore succeeded in preserving a greater number of 

 the characteristic life-features of the Oolites than any other 

 country with which we are acquainted. 



LITERATURE. 



The following list comprises some of the more important sources of 

 information as to the rocks and fossils of the Jurassic series : 



(1) ' Geology of Oxford and the Thames Valley.' Phillips. 



(2) ' Geology of Yorkshire,' vol. ii. Phillips. 



(}) ' Memoirs of the Geological Survey of Great Britain.' 



(4) ' Geology of Cheltenham.' Murchison, 2d ed. Buckman. 



(5) ' Introduction to the Monograph of the Oolitic Asteriadae' (Palseon- 



tographical Society). XVright. 



(6) " Zone of Avicula contorta and the Lower Lias of the South of 



England " ' Quart. Journ. Geol. Soc.,' vol. xvi., 1860. Wright. 



(7) "Oolites of Northamptonshire" ' Quart. Journ. Geol. Soc.,' vols. 



xxvi. and xxix. Sharp. 



(8) 'Manual of Geology.' Dana. 



(9) 'Derjura.' Quenstedt. 



(10) ' Das Flotzgebirge WilrUembergs.' Quenstedt. 

 (n) 'Jura Formation.' Oppel. 



