92 STUDIES IN GEOLOGY, No. i 



not otherwise known in the fossil state, with about 20 

 existing species of shrubs and trees of tropical and sub- 

 tropical regions of South America. The present species 

 occurs at both Corocoro and Potosi. 



Order R O S A L E S 



Family ROSACES 



Genus Osteomeles LINDLEY 



Osteomeles pliocenica sp. nov. 



PLATE VII Fig. 3. 



Description. Leaves spatulate or obovate in general 

 outline, widest above the middle, with a rounded or bluntly 

 pointed apex and a narrow, long cuneate, acute base. 

 Margins entire except distad, irregularly and sparingly 

 crenulate near the apex. Texture coriaceous. Length 

 ranging from 12 mm. to 15 mm. Maximum width rang- 

 ing from 4.5 mm. 7.5 mm. Petiole stout, 6 mm. in 

 length in the largest specimen. Secondaries stout, largely 

 immersed, diverging at acute angles of 15 to 20, anasto- 

 mosing to form distally elongated reticulations. 



This species is abundant at both Potosi and Corocoro, 

 and a second species occurs in what I regard as somewhat 

 younger deposits at Jancocata, Bolivia. There are about 

 a score of existing species, often referred to the genus 

 Hesperomeles, the majority of which are unarmed or 

 spinescent shrubs of the Cordillera region ranging from 

 Central America to Bolivia. Among these the fossil is 

 most similar to Osteomeles cuneata (Lindley) Decaisne (i) 

 of the Peruvian Andes, in fact there are no obvious differ- 

 ences between the fossil and living leaves except the 

 longer petioles of the former. Less closely related are the 

 leaves of the existing Osteomeles pernettyoides (Wedd.) 



1 Decaisne, Nouv. Arch. Mus. Hist. Nat. Paris, tome 10, p. 184, 1874. 



