96 STUDIES IN GEOLOGY, No. i 



Genus Mimosites BOWERBANK 

 Mimosites engelhardti BERRY 



PLATE VII Figs. 9, 10. 



Mimosites linearis Engelhardt, Sitz. Naturw. Gesell. Isis in Dres- 

 den, 1894, Abh. i, p. 13, pi. i, figs. 21, 35 (not M. linearifolius Les- 

 quereux, 1878. M. linearis Knowlton, 1898). 



Mimosites engelhardti Berry, Proc. U. S. Natl. Ms., vol. 54, p. 

 133. Pi- 15, %. 22, 1917. 



Description. Leaflets sessile, linear-lanceolate, slightly 

 inequilateral, with an acuminate-cuspidate tip and an 

 acuminate base. Margins entire. Texture coriaceous. 

 Length, 12 to 15 mm. Maximum width, 2 to 3 mm. Mid- 

 rib relatively stout. Secondaries obsolete by immersion. 



The name of this species appears to be preoccupied by 

 the Mimosites linearifolius of Lesquereux (i) from the 

 Green River Eocene of Wyoming, which Knowlton (2) 

 amended to Mimosites linearis in 1898. While Engel- 

 hardt named his form in 1894, it seemed desirable to 

 rename it in order to avoid confusion. 



This species is abundant at Potosi, always in the form 

 of detached leaflets, and it occurs sparingly at Corocoro. 

 It is very similar and liable to be confused with other 

 leguminous leaflets found at Corocoro namely, Acacia 

 wmnervifotia- Engelhardt and Mach&rium criocarpoides 

 Engelhardt, and as previously remarked, may represent a 

 variant not entitled to specific rank. The first is more 

 narrowly elongate and lanceolate, with more prominent 

 camptodrome secondaries. The second is relatively shorter 

 and wider, petiolulate, more lanceolate, and with more 

 prominent secondaries. 



1 Lesquereux, L., Tertiary Flora, 1878, p. 300, pi. 59, fig. 7. 

 "Knowlton, F. H., Bull. 152, U. S. Geol. Survey, 1898, p. 144. 



