184 STUDIES IN GEOLOGY, No. 4 



Engler segregates them in ten unnatural sections with im- 

 possible names. Their distribution includes tropical and 

 South Africa, Madeira, Madagascar, Mauritius and Bour- 

 bon; India to Australia; New Zealand and Norfolk Island; 

 the Sandwich Islands ; southern Florida, the Bahamas and 

 Antilles, and tropical South America to southwestern Brazil. 



The genus is one of great interest since its distribution not 

 only suggests antiquity, which is borne out by what little is 

 known of the geological record, but also suggests that the 

 genus represents at the present time the survivors of one of 

 the formerly cosmopolitan and synthetic types of the family. 

 The fossil record of forms specifically assigned to the genus 

 Sideroxylon is meager, although other genera of Sapotacese, 

 and particularly the form-genus Sapotacites, go back to Up- 

 per Cretaceous times. 



The oldest forms referred to Sideroxylon are two species 

 from the lower Eocene of the Mississippi embayment re- 

 gion. 21 There are four recorded species from the Oligocene 

 of Central and southern Europe, and two or three species 

 from the Miocene of southern Europe. The Bolivian fossil 

 species, although fragmentary, is well marked. 



Genus CHRYSOPHYLLUM Linne 



Chrysophyllum crassum Berry, sp. nov. 



PLATE VII Fig. 6 



Leaves of medium to small size, symmetrical-oval in out- 

 line, widest in the middle, narrowing equally distad and 

 proximad. Base broadly cuneate. Apex abruptly acumin- 

 ate. Margins entire, full and evenly rounded. Texture pol- 

 ished and coriaceous. Length about 6 cm. Maximum width 

 about 3.2 cm. Petiole missing. Midrib stout and prominent. 

 Secondaries mediumly stout, but largely immersed in the leaf 

 substance and not nearly so prominent as might be inferred 

 from the way they are outlined on the photograph ; they 



21 Berry, E. W., U. S. Geol. Surv. Professional Paper 91, pp. 334- 

 335, pl- 99, fig- 45 pl. ioo, fig. 8, 1916. 



