MARSUPIALIA 



307 



has given the key to the nature of the "palates" from our 

 oolites, now recognized as the teeth of congeneric larger forms 

 of cartilaginous fishes. 

 Mr. Broderip, in his 

 Memoir above quoted, 

 observes, "that it may 

 not be uninteresting 

 to note that a recent 

 species of Trigonia 

 has very lately been 

 discovered on the 

 coast of Australia, 

 that land of marsupial ™ 

 animals. Our speci- 

 men lies imbedded 

 with a number of 

 fossil shells of that 

 genus." Not only 

 Trigonia} but Tercbra- 

 tulce exist, and the 

 latter abundantly, in 

 the Australian seas, 

 yielding food to the 

 Cestracion, as their 

 extinct analogues 

 doubtless did to the 

 allied Plagiostomes 

 with crushing teeth, 

 called A croclus, Psam- 

 modus, etc. Arau- 



Fig. 87. 

 {After Fitton.) 

 i. Rubbly limestone (cornbrash). 



2. Clay, with Terebratulites. 



3. Limestone rock. 



4. Blue clay. 



5. Oolitic rock. 



6. Stiff clay. 



7. Oolitic rag, or limestone. 



8. Sandy bed containing the Stonesfield slate. 



carice and cycadeous plants, like those found fossil in oolitic 

 beds, flourish on the Australian continent, where marsupial 

 quadrupeds now abound ; and thus appear to complete a 

 picture of an ancient condition of the earth's surface, which 



