MARYLAND GEOLOGICAL SURVEY 809 



botanical affinities, considerable stratigraphic value, since it is found to 

 characterize the Magothy formation at a large number of outcrops from 

 jSTew Jersey to Maryland. It occurs also in the Middendorf beds of South 

 Carolina. 



Occurrence. MAGOTHY FORMATION. Deep Cut, Delaware; Grove 

 Point, Cecil County, Maryland. 



Collection. Maryland Geological Survey. 



Order ARALES 

 Family ARACEAE 



Genus PISTIA Linne 

 [Sp. PL, 1753, p. 963] 



PISTIA NORDENSKIOLDI (Heer) Berry 

 Plate LVI, Fig. 3 



Chondrophyllum nordenskioldi Heer, 1874, Fl. Foss. Arct., Bd. iii, Ab. ii, 



p. 114, pi. xxx, fig. 4b; pi. xxxii, figs. 11, 12. 

 Chondrophyllum nordenskioldi Berry, 1907, Bull. Torrey Bot. Club, vol. 



xxxiv, p. 198, pi. xiii, fig. 1. 

 Pistia nordenskioldi Berry, 1910, Ibidem, vol. xxxvii, p. 189, pi. xxi, figs. 



1-15. 

 Pistia nordenskioldi Berry, 1911, Ibidem, vol. xxxviii, p. 405. 



Description. " P. foliis ovalibus, integerrimis, basi attenuatis, nervis 

 primordialibus quinque, duobus lateralibus basi connatis." Heer, 1874. 



This species, based on a few incomplete specimens from the Atane beds 

 of Greenland, was described by Heer in 1874. Thirty-three years later 

 the writer identified it in a small collection from the Cretaceous of North 

 Carolina. In 1907 and 1908 it was found to be exceedingly abundant in 

 the Black Creek formation of North Carolina, and this abundant material 

 has enabled the writer to settle its botanical position and to somewhat 

 amplify Heer's diagnosis. 



The leaves are elliptical or orbicular in outline, with a broadly rounded 

 or slightly truncated apex and a decurrent base, which is broad and flat 

 for a distance of about 1 cm. Total length of leaf varying from 3 cm. to 

 6 cm., averaging about 4.5 cm. Maximum width ranging from 2 cm. to 



