52 STUDIES IN GEOLOGY, No. 4 



Genus WEICHSELIA Stiehler 



Weichselia peruviana (Neumann) Zeiller 



PLATE I, PLATE II Figs, i, 2 



Weichsclia mantelli Bravo (non Brongniart) Bol. Cuerpo Ing. d. 

 Minas, No. 35, pp. 109-110, 1906. 



Equisetites peruanus Neumann, Neues Jahrb. Beil. Bd. 24, p. 78, 

 pi. 2, figs, i, 2, 1907. 



Weichselia Mantelli Neumann (non Brongniart), Idem., p. 74, pi. 

 i, figs. la, b. 



Pecopteris weichselia Lukis, Bol. Cuerpo Ing. d. Minas, No. 64, 

 plate facing page 18, 1908. 



Weichselia reticulata Zeiller, Compt. Rendus, tome 150, p. 1488, 

 1910. 



Weichselia (?) cf. Mantelli Salfeld, Gesell. Erdkunde Leipzig, Bd. 

 7, p. 214, 1911. 



Weichselia peruviana Zeiller, Revue Gen. Bot. tome 25 bis, p. 10, 

 figs. D, D2, Empl. 21, figs. 2-13, 1914. 



? Weichselia rtiantelli Schlagintweit, Centralb. Min. Geol. & Pal. 

 Nos. 19-20, pp. 315-319, 19*9- 



This species has been rather fully described by Zeiller (op. 

 cit.) and it would seem that the characters disclosed are 

 sufficient to warrant its specific segregation from Weichselia 

 reticulata , or mantelli as many prefer to call it. 



These features have been observed only in the material 

 from near Lima but in view of the great abundance of 

 Weichselia at many localities in Peru all of which appear to 

 be of approximately the same age, the probability is all in 

 favor of these occurrences representing a single species, and 

 I have treated them as such in the accompanying citations of 

 synonymy and occurrences. 



Material collected by me from Pinonate and San Lorenzo 

 is in form of impressions and the venation is seldom clear. 



Material from Jatunhuasi has the very thick pinnules pre- 

 served and when these break away from the shale the ven- 

 ation is very distinct on the impressions of the under side of 

 the pinnules. The veins aside from mid-vein are thin but the 

 pinnule substance is arched in areolse, giving impressions the 

 appearance of inordinately stout veins. 



