126 STUDIES IN GEOLOGY, No. 4 



These leaflets, presumably because of their more perishable 

 nature, are much rarer than the pods with which they are 

 associated. The latter are exceedingly common but beyond 

 finding the two in association in the same hand specimen no 

 evidence of their identity is available. I have consequently 

 described the leaflets and pods under distinct specific names, 

 although I have combined them in the accompanying restor- 

 ation. 



Cassia has between 300 and 400 existing species, found in 

 the warmer temperate and tropical regions of all the conti- 

 nents and especially abundant in tropical America. Their 

 place of origin is unknown, since they make their appear- 

 ance in the Upper Cretaceous almost simultaneously in New 

 Zealand, Australia, Bohemia, Saxony, Greenland, the Atlan- 

 tic Coastal Plain, and the Dakota sandstone of the Rocky 

 Mountain province. More than 100 fossil species are already 

 known. The Eocene distribution sheds no light on the early 

 history of the genus, for species occur in such widely separ- 

 ated regions as North America, Europe, and Australia. 

 There are numerous Oligocene and Miocene species, the 

 Oligocene records being confined to Europe and Africa and 

 the Miocene records being confined to Europe and America. 

 Cassia was abundant along the shores of the Pliocene Medi- 

 terranean of Europe, and 4 species are recorded from South 

 American beds which are thought to be of Pliocene age. 

 Pleistocene species are recorded from Maryland, and also 

 from the East Indies (Java), where they are associated with 

 Pithecanthropus erectus Dubois. One fact is certain the 

 genus has been a part of the American flora since the dawn 

 of the Upper Cretaceous, and has probably been present in 

 South America since the dawn of the Tertiary. The present 

 species along with its associates is indicative of warmer 

 climatic conditions than prevail at the present time in south- 

 ern Chile. 



Arauco mine, Curanilahue. 



