88 STUDIES IN GEOLOGY, No. 4 



They are of exceeding interest but are unfortunately 

 represented by a scanty amount of material, that of the Pteris 

 being the most extensive and satisfactory. The Gleichenia 

 (referred to Pecopteris by Engelhardt) is represented by a 

 single specimen which fails to show the dichotomous habit 

 and is to that extent inconclusive. The pinnae are Gleichen- 

 oid but the veins are simple and possibly may be more prop- 

 erly referable to the Cyatheacese. 



The Cyathoides presents remarkable similarities to the 

 monotypic Thyrsopteris of the Juan Fernandez islands. The 

 family includes the existing tree ferns of South America 

 which are particularly prominent in the rain forests of the 

 montana country from Bolivia northward. The Blechnum 

 has been compared with the existing Blechnum longifolimn 

 H.B.K., which ranges from the Antilles and Central America 

 in the rain forest country to the Amazon basin, and the mon- 

 tana of eastern Peru. There are a large number of existing, 

 mostly tropical, species, and the genus is well represented 

 and confined in South America to the same general region as 

 Blechnum longifolium. 



The Adiantites is represented by rather dubious material 

 that suggests the existing Adiantum macrophylluni Sow., 

 which ranges from Central America to eastern Peru and 

 Brazil. 



The Pteris is well preserved and very similar to the exist- 

 ing Pteris grandifolia Linne, with a range simliar to the 

 preceding. 



Cycads are not common fossils in Tertiary deposits any- 

 where and it is therefore important to verify Englehardt's 

 reference of a scrap to the genus Zctniia by the discovery of 

 abundant and well preserved material at Curanilahue. Zamia 

 is the dominant existing cycad genus of the Western Hemi- 

 sphere with upwards of two score species ranging from pen- 

 insular Florida and Mexico to Brazil and Bolivia. It is 

 probably not related to the older fossil forms of the genus 

 Zamites, but evidently had a more extensive range in the 



