170 STUDIES IN GEOLOGY, No. 4 



These leaves are exceedingly abundant in matted layers in 

 the water laid part of the section, and are exceedingly well 

 characterized. I saw very many exceedingly handsome and 

 complete specimens that I was unable to bring away with me 

 because of the friable nature of the material. Other genera 

 that have leaves which approach the fossil more or less 

 closely are Gouania of the Rhamnacese, Luhea of the Tilia- 

 ceae, and Hura of the Euphorbiacese, as well as other genera 

 that it is needless to mention. None of these, however, are 

 close enough to be considered in detail and the majority have 

 toothed margins. I mention Gouania in particular since 

 Engelhardt has referred to it 14 two species from the Mio- 

 cene of Santa Ana in the Magdalena valley of Colombia. 

 These have a very similar venation to that of the present 

 species, as is true of a number of other existing Rhamna- 

 cese, but are smaller leaves with toothed margins. This 

 resemblance to the smaller leaves of Coussapoa pliocenica is 

 heightened by the tendency of the latter to break along the 

 veins around the margins and thus to simulate toothing. The 

 Pisllypampa leaves are, however, entirely distinct from those 

 of Gouania. 



The genus Coussapoa contains about 15 existing species 

 of shrubs or trees that are confined to the Central and South 

 American tropics. It is rather poorly represented in Amer- 

 ican herbaria, consequently I am unable to indicate the exist- 

 ing species that is most similar to the fossil. The Central 

 American species that I have seen have pinnate secondaries, 

 but certain South American forms are said to have basal 

 lateral primaries, and they are incipiently developed in the 

 only additional fossil species of Coussapoa which I described 

 recently 15 from the Miocene of Venezuela. Engelhardt in 



14 Engelhardt, H., Abh. Senck. Naturf. GeselL, Bd. 19, pp. 33, 34, 

 pi. 4, figs. 4-7, 1895. 



"Berry, E. W., Proc. U. S. Natl. Mus., vol. 59, p. 563, fig. 2, pi. 

 108, figs. 1-4, 1921. 



