58 The Rock Record 



horses and elephants. And everyone remembers how 

 Darwin digging fossils on the pampas was impressed 

 by the resemblance between the extinct and extant 

 sloths and ant-eaters. "This wonderful relationship," 

 he wrote, "in the same continent between the dead and 

 the living will, I do not doubt, hereafter throw more 

 light on the appearance of organic beings on our 

 earth, and their disappearance from it, than any 

 other class of facts." This was a prophetic utterance. 

 The palaeontologist has not only deciphered a very 

 difficult ancient record, he has thrown the light of 

 the past on the present. 



What a thrill there must have been in the world of 

 naturalists when Archaeopteryx was discovered in 

 Jurassic strata in Bavaria — an extinct bird linking 

 the creatures of the air back to the reptiles of the 

 earth. For it had teeth in both jaws, a long lizard- 

 like tail, and a half-made wing. It is by no means true 

 that connecting links are always missing. 



There is something eloquent too in the persistence 

 of what may be called "living fossils," creatures like 

 the king crab (Limulus), the lungfishes (Dipnoi), 

 and the New Zealand "Lizard" (Sphenodon), sole 

 survivors of ancient races which were once abun- 

 dantly represented. Of the ancient order of fringed- 

 finned fishes (Crossopterygii) which were abundant 

 in the Old Red Standstone Age, and are included by 

 some in the ancestry of Amphibians, only two remain 

 in modern times — Polypterus and Calamichthys, in 

 African rivers. 



