SEDIMENTATION, ENVIRONMENT, AND EVOLUTION. 21 



support when trilobites have been found in the stomachs of 

 fossil fishes, and we are thereby tempted to trace a causal 

 connexion . 



In the matter of the broader aspects of evolution, it was 

 suggested by J. Starkie Gardner* that the expansion, migration, 

 and consequent evolution of the ruminants waited upon the rise 

 of the grasses, and only when the latter became widespread 

 in Eocene and Oligocene times was the food-supply of these 

 animals ensured and migration and expansion of the stock 

 possible. Again, Professor E. W. Berry, in a suggestive paper 

 on " The Evolution of the Flowering Plants and Warm-blooded 

 Animals," recently published, t has put forward tentative views 

 to the effect that the rise of the birds was dependent upon the 

 production of a food-supply in the shape of the fruits of the 

 flowering plants, and thus followed that stage in the evolution 

 of plants. He also suggests that the differentiation of the 

 Eocene mammals was possible only because of the food value 

 of such fruits, and, noting the concentration of energy in 

 grain, points out that human development was not possible 

 without it. 



In his recently-published monograph on " The Environ- 

 ment of Vertebrate Life in the Late Palaeozoic in North 

 America,"J Professor E. C. Case describes the change which 

 took place in the fauna from the long period of slow evolution 

 in the singularly monotonous environment of the marine 

 Pennsylvanian to the rapid evolution in the diversified environ- 

 ment of the Permo-Carboniferous. He regards the sudden 

 expansion as due to climatic change accompanied by physio- 

 graphic changes which led to an alteration in the level of the 

 continent. He points out that in land life adapted to arid 

 climatic phases we should expect to find a greater activity 



* Proc. Geol. Assoc, Vol. 9, (1885-6) p. 448. 



f Amer. Journ. Science, Series 4, Vol. 49, p. 207 (1920). 



J Carnegie Institution Publications, No. 283 (1919). 



