EXTENSIONS OF DARWINISM 285 



and complexity of branching, till they culminated in tlic great 

 Irish elk, which was the contemporary of the mammoth and 

 man in our own country. 



Dr. A. S. Woodward, keeper of Geology in the British 

 Museum, discussed this curious phcnumenou in his presi- 

 dential address to the Geological Section of the British Asso- 

 ciation in 1909 ; and a few extracts will show how widespread 

 are these facts, and the great interest they have excited. 

 After sketching out the whole course of animal development, 

 and showing how universal is the law (much empliasised by 

 Darwin), that the higher form of one group never developed 

 from similar forms of a preceding lower type, but that both 

 arose from an early, more generalised type, he says: 



*' To have proved, for example, that flying reptiles did not pass 

 into birds or bats, that hoofed Dinosaurs did not change into 

 hoofed mammals, and that Ichthyosaurs did not become porpoises, 

 and to have shown that all these later animals were mere mimics 

 of their ^predecessors, originating independently from a higher yet 

 generalised stock, is a remarkable achievement." 



Then comes a reference to the subject we are now discuss- 

 ing: 



" Still more significant, howeve-r, is the discovery, that towards 

 the end of their career through geological time, totally difTerent 

 races of animals repeatedly exhibit certain peculiar features which 

 can only be described as infallible marks of old age. The growth 

 to a very large size is one of these marks, as we observe in the 

 giant Pterodactyls of the Cretaceous i^eriod, the colossal Dinosaurs 

 of the Upper Jurassic and Cretaceous, and the large mammals of 

 the Pleistocene and the present day. It is not, of course, all the 

 members of a race that increase in size; some remain small until 

 the end, and they generally survive long after the others are ex- 

 tinct. 



"Another frequent mark of old age In races was first discussed 

 and clearly pointed out by Professor C. E. Beechor of Yale. It is 

 the tendency of all animals with skeletons to produce a superfluity 

 of dead matter, which accumulates in the form of spines or bosses 



