212 STUDIES IN GEOLOGY, No. 4 



the swamps along the Desaguedero River (upper limit 4,000 

 meters), the Chusquea (Bambusese) of the Chaco country 

 of eastern Bolivia (upper limit of 3500 meters), and the 

 Cortaderia (Festucese, upper limit 4000 meters). The pres- 

 ent climate at Jancocata is too dry for any of these. 



I have recorded a very similar Phragmites from Potosi 4 

 and at the latter locality there are also many grass leaves 

 (Poacites) and a wned scales (Festuca). 



Class DICOTYLEDONS 



Order FAGALES 

 Family BETULACES 



Genus ALNUS Linne 



Alnus preacuminata Berry, n. sp. 



PLATE I Fig. 6 



It is scarcely possible to frame a diagnosis of the incom- 

 plete material to which I am giving the above name. I have 

 compared the material with all of the vegetation which exists 

 at the present time on the altaplanicie of Bolivia without 

 result, and it might, without any great stretching of the facts 

 be called Alnus jorullcnsis, Alnus mirbelii or Alnus acum- 

 inata. To avoid the nomenclatorial tangle in which these 

 modern species appear to be involved my course appears to 

 be the most desirable. 



The alder, generally of large size, is not uncommon in the 

 mountain valleys of Peru and Bolivia where there is suf- 

 ficient moisture. I have no measure of this but noted the 

 presence of Alnus in the Araca valley at 10,000 feet. What 

 is called Alnus mirbelii Spach is cultivated at 13,000 feet 

 at Sacaba. What is called Alnus acuminata H. B. K., grows 

 naturally at Co tana, Bolivia at 8,000 feet, and a specimen 

 from the last locality bearing this name in the Bang collec- 

 tion from Bolivia (No. 1893) is identical with the fossil. 



4 Berry, E. W., U. S. Natl. Museum Proc., vol. 54, p. 122, pi. 15, 

 fig- 5, 



