140 



MIOCENE CLIMATE. 



Of these stations there is not any one which exactly repre- 

 sents the climate of the Swiss Miocene district ; but we approxi- 

 mate to it by ascertaining with what existing climatal conditions 

 it was probably most in accordance. The mixture of tropical 

 plants with plants of the temperate zones indicates that the 

 winters were mild and the summers not very hot ; the climate was 

 that of a coast or an island. The winter, however, was probably 

 rather colder and the summer a little warmer than is the case 

 at present in the Atlantic islands of Madeira &c.; so that the 

 best standard by which to judge of the conditions of temperature 

 for the Lower Miocene would be furnished by New Orleans, 

 and in the Old World by Tunis. For the Upper Miocene, 

 Savannah and Messina would furnish the most suitable points 

 of comparison to determine the temperature of that portion of 

 the Swiss Tertiary district. 



At the present time the very great difference of elevation of 

 the land and the influence of the snow-clad chain of the Alps 

 form, as it were, a barrier against the Miocene climate of Swit- 

 zerland. The following summary explains these conditions : 



Estimating the refrigerant influence of the mountains at JC. 

 (or nearly 1 Fahr.) we should probably have in Northern Swit- 



