Tratis. N. V. Ac. Set. 94 Apr/l 14, 



many other facts into one theory in which each bears a definite and 

 important relation. In its entirety I claim it as new, and as differing 

 widely from all that have preceded it. 



DISCUSSION, 



The President stated that he had been led to think that not quite 

 so much uniformity of climate had prevailed in former periods as 

 is often supposed. A very warm temperature had existed at the 

 north in Tertiary times. However, there had been also great vari- 

 ation in lower latitudes, ranging from tropical heat to a very cold 

 climate when the ice overspread the land. But no evidence had 

 been shown that these temperatures were synchronous. A remarka- 

 ble fossil fauna of tropical character had been discovered by BON- 

 Pl.AND in Bogota ; but we were not in possession of facts permitting 

 us to assert that these ammonite deposits of South America were 

 laid down at the same time as those in the North. There was, on the 

 other hand, considerable evidence of the occurrence of alternations of 

 climate. High tides of temperature had existed certainly in different 

 parts of the globe, but there was no evidence that these had occurred 

 at the same time. Thus the discovery of bodies of floodwood, left by 

 earthquake waves at high points on different coasts, would be no evi- 

 dence that these were deposited by the same flood over the whole 

 globe. 



In Palaeozoic time, comparatively moderate irregularities in temper- 

 ature had prevailed, the sea being more uniformly distributed over 

 the surface. During the Carboniferous period, the temperature was 

 moist and equable, producing a luxuriant vegetation, but favorable 

 also to the preservation of vegetable deposits. At the present day, 

 peat accumulates in the greatest quantity wherever the climate is 

 cool, moist, and equable — therefore, not in the tropics, where the wood 

 is burned up under present conditions, and where it was not accumu- 

 lated during the Coal-period. 



The plants of the Cretaceous were similar to those of the present 

 day ; many genera in fact were identical with those now growing, 

 e.^., the sassafras, magnolias, liriodendrons, etc. There was no evi- 

 dence of a tropical vegetation in the early Cretaceous. Later, how- 

 ever, palms and other tropical forms began to appear. The climate 

 was in general of a temperate character. 



The Tertiary deposits were characterized by a luxuriant though not 

 tropical vegetation, such as is found in warm climates at the present 

 day. Thus the deciduous cypress now reaches as far north as our 

 Central Park in this city, but its natural habitat is further south. In 



