Maryland Geological Survey 345 



Zamites tenuinervis Fontaine 

 Plate LIV, Figs. 1-5 



Zamites tenuinervis Fontaine, 1890, Mon. U. S. Geol. Survey, vol. xv, 1889, 



p. 171, pi. Ixvii, fig. 1; pi. Ixix, fig. 2; pi. Ixx, fig. 1; pi. Ixxv, fig. 3; pi. 



Ixxvi, fig. 7; pi. Ixxvili, fig. 6; pi. Ixxxiv, fig. 7. 

 Zamites distantinervis Fontaine, 1890, toe. cit., p. 172, pi. Ixxxiii, fig. 4. 

 Zamites suifalcatus Fontaine, 1890, loc. cit., p. 173, pi. Ixxxiv, fig. 13; pl. 



Ixxxv, fig. 3, 

 Zamites tenuinervis Fontaine, 1893, Proc. U. S. Nat. Museum, vol. xvi, p. 



267, pl. xxxvii, figs. 3, 4; pl. xxxviii, figs. 1, 2. 

 Zamia washing toniana Ward, 1895, 15th Ann. Rept. U. S. Geol. Survey, p. 



350, pl. ii, fig. 6. 

 Zamites tenuinervis Penhallow, 1902, Trans. Roy. Soc, Can., series ii, vol. 



viii, sec. iv, p. 42. 

 Zamites tenuinervis Fontaine, 1906, in Ward, Mon. U. S. Geol. Survey, vol. 



xlviii, 1905, pp. 257, 548 (?), pl. Ixviii, figs. 2, 3 (non p. 528). 

 Zamia washingtoniana Fontaine, 1906, in Ward, loc. cit., p. 503 (pars), pl. 



cxi, fig. 1 (non fig. 2). 

 Podozamites distantinervis Fontaine, 1906, in Ward, Mon. U. S. Geol. Surv., 



vol. xlviii, 1905, p. 573 (non balance of citations). 



Description. — Pinnae always found detached, very long and relatively 

 narrow, somewhat falcate. Apex not preserved in the Maryland or 

 Virginia material. In a specimen from the Glen Rose beds of Texas, 

 identified as this species by Fontaine, an obtusely rounded tip with con- 

 vergent veins is shown. Base inequilateral, narrowed, and abruptly 

 rounded, somewhat variable. Length presumably 20 cm. or more, of the 

 longest fragments preserved one is 15.5 cm. without showing the extreme 

 base or any evidence of apical narrowing, while another rather obscure 

 specimen, also lacking the extreme base or apex, is 20.5 cm. in length. 

 Width from 1.2 cm. to 2.3 cm., averaging about 2 cm. Veins parallel 

 throughout most of their length, numerous, forked at their extreme base. 

 Texture coriaceous. 



This species is rather common in the Potomac Group, being espe- 

 cially abundant in the Patuxent formation at Fredericksburg, Virginia, 

 and in the Glen Rose beds of Texas. All of the specimens are detached 

 and more or less fragmentary. Their distinctness from Podozamites is 

 not conclusive, although a number seem to show evidence of a ' basal 

 callosity, and altogether lack the contracted and more or less elongated 



