THE CRETACEOUS PERIOD. 175 



for any large part of the animal life. The seeds of the conifers are 

 indeed much eaten by certain birds and rodents, but their foliage 

 is little sought by the leading herbivores. The introduction, there- 

 fore, of the dicotyledons, the great bearers of fruits and nuts, and of 

 the monocotyledons, the greatest of grain and fodder producers, was 

 the groundwork for a profound evolution of herbiverous and frugiverous 

 land animals, and these in turn, for the development of the animals 

 that prey upon them. A zoological revolution, as extraordinary as 

 the phytological one, might naturally be anticipated, but it did not 

 immediately follow, so far as the record shows. The reptile hordes 

 seem to have roamed through the new forests as they had through 

 the old, without radical modification. The zoological transformation 

 may have been delayed because animals suited to the proper evolu- 

 tion had not then come into contact with the new vegetable realm; 

 but with the opening Tertiary, the anticipated revolution appeared, 

 and swept forward with prodigious rapidity. 



The new flora became very widely and uniformly distributed. 

 Not only was the European flora essentially the same as the Ameri- 

 can, but there was a close resemblance between the flora of Mid-Green- 

 land (70°-72° Lat.) and that of Maryland and Virginia. That there 

 should be no essential variation in a stretch of 35° of latitude implies 

 climatic conditions of remarkable uniformity. The flora, in its gen- 

 eral nature, was nearest to that which now flourishes at about 30° 

 latitude, that is, a flora of a sub-tropical type. As this seems to 

 have been attended by low relief of the land, widely extended epi- 

 continental seas, extensive calcareous deposition, and slow consumption 

 of carbon dioxide in rock solution and carbonation, there was present 

 the combination of conditions regarded as favorable for a mild, uni- 

 form climate. 



The land animals. — The terrestrial animals continued to bear the 

 same general aspect as they did in the Jurassic and Comanchean. In 

 Europe, where the sea made great inroads upon the land, there was 

 some decline in the abundance, variety, and gigantic proportions of 

 the land animals, but in America, where the incursion of the sea was 

 more limited, and where the post-Jurassic deformation of the west 

 made some compensation for sea-advance elsewhere, the land area 

 remained sufficiently large to permit the evolution of the reptilian 

 host to proceed with little restraint. On both continents, however, 



