90 STUDIES IN GEOLOGY, No. i 



Texture very coriaceous. Length, about 4 cm. ; maximum 

 width, in the middle part of the leaf, about 3 mm. Midrib 

 stout, impressed on the upper surface. Secondaries longi- 

 tudinally parallel, 5 or 6 equally spaced in each half of the 

 lamina. 



This characteristic species is represented, usually by frag- 

 ments, which occur at both Potosi and Corocoro. It is clearly 

 referable to Podocarpus, belonging to the section Eupodo- 

 carpus of Endlicher, and is comparable with the existing 

 Podocarpus lamberti Klotzsch of middle and southern Brazil 

 and also Podocarpus oleifolius Decaisne which is not uncom- 

 mon in the montana of Peru and Bolivia and which I found 

 growing freely at Ayapampa in the mountains south of 

 Cochabamba at altitudes of 9000 feet. 



The existing forms of Podocarpus number over 40 

 species and they are as dominant representatives of the 

 Coniferales in the Southern Hemisphere as are the pines 

 in the Northern. They extend northward to China and 

 Japan through the East Indian region and to Jamaica and 

 Central America in the Western Hemisphere, and have 

 representatives in all three of the great southern land 

 masses, as well as in Madagascar and New Zealand. This 

 distribution is suggestive of a long geological history in 

 keeping with which certain forms from the British Jurassic 

 and Lower Cretaceous and the American Lower Creta- 

 ceous, are referred to the genus Nageiopsis and 

 considered as the prototypes of the Nageia section of 

 Podocarpus, which should probably be raised to its former 

 position of generic rank. Some 15 or more fossil species of 

 Popocarpus have been described, chiefly from the European 

 Tertiary, and no conclusively identified fossil forms, other 

 than the present species, have been discovered on the 

 American continents. The section Hupodocarpus (Endli- 

 cher) to which the present fossil species belongs comprises 

 over 30 existing species, almost as widely distributed as 

 the genus, with several West Indian and South American 



