PALEONTOLOGY 107 



history of some of the animals that are found in the 

 geological record. 



From the fact that the Trilobites, so highly organ- 

 ized, appeared in the Primordial, it would seem that 

 they were specially adapted to make progress. They 

 lived through Paleozoic Time, which, according to 

 Dana, represents twelve of the sixteen parts of all 

 geological time, beginning with the Primordial; or, 

 calling the whole geological time 48 millions of years, 

 the Trilobites lived 36 millions of years, or three- 

 fourths of all geological time. From their great per- 

 sistence in time it would seem that they had a remark- 

 ably good opportunity to make wonderful progress in 

 structure. During that time there were thousands of 

 species, yet they made no progress. We do not know 

 that in all those millions of years a single higher form 

 was evolved from any one of the great multitude of 

 species of Trilobites. As Darwin says of the goose, 

 so I say of the Trilobite; it " had a singularly inflexi- 

 ble organization." 



The remarkable thing about this, however, is that 

 previous to the Primordial, while it was becoming a 

 Trilobite it must have had a singularly flexible organi- 

 zation, otherwise it could not have obtained its com- 

 plex structure; but when it reached the Primordial it 

 became very conservative. 



It is strange beyond belief that an animal which 

 was making such wonderful strides on the road of 

 evolution, outstripping every competitor except the 

 Orthoceras, should suddenly lose all power to progress 

 in structure and still live on with little change through 

 most of geological time. 



The lingula, a brachiopod, has existed through all 

 geological time — from the Primordial to the pres- 

 ent — and has made no progress in organization. Liv- 

 ing lingula are nearly identical in form with those of 



