2 ID STUDIES IN GEOLOGY, No. 4 



DESCRIPTION OF THE FOSSIL PLANTS 



Phylum Pteridophyta 



Class LEPTQSPORANGIAT.E 



Order POLYPODIALES 



Family POLYPODIACE^E 



Genus PTERIS (authors) 

 Pteris pacajensis Berry sp. nov. 



PLATE I Figs. 7, ja. 



I use the generic term Pteris in a somewhat generalized 

 sense, fully realizing that the existing forms formerly re- 

 ferred to Pteris have been segregated into a number of gen- 

 era. It seems highly undesirable to attempt anything more 

 with fossil forms like that under consideration than to indi- 

 cate the general affinity by the use of the older and broader 

 generic term. The present material, which is limited, may be 

 described as follows : 



Pinna divided to within about i mm. of the rachis into 

 remote, lanceolate segments. These make an angle of about 

 60 to 70 degrees with the rachis, and are separated by wide, 

 evenly rounded and nearly equilateral sinuses. Rachis stout, 

 prominent. Lobes about 1.25 cm. in length and 2.5 mm. in 

 maximum width. Midveins stout, sending off at acute 

 angles numerous laterals, some of which are simply once 

 forked and others are connected by cross veinlets to form a 

 netted venation of the type known as "dictyopteroid." There 

 are a few simple or furcate veins in the wings that connect 

 the lobes at the base of the sinus, but this region is so nar- 

 rowed in the present material that it is largely without veins 

 and the lobes are to all intents pinnules. Possibly in more 

 proximal parts of the frond the lamina may have been wider. 

 The lateral veins run directly to the margins, which are en- 

 tire, and at their tips they are conspicuously expanded and 

 show every indication of the former presence of marginal 

 sori. 



