Maryland Geological Survey 369 



This species was based upon rare specimens from near Potomac Run, 



Virginia, and a single specimen was afterward recorded from Alum 

 Rock in that State. The Maryland occurrence is based upon Fontaine's 

 record of a single doubtful specimen, which the writer has been unable to 

 find. The species is of doubtful value at best, and is included in the 

 Maryland flora with some hesitation and for the sake of completeness. 



Occurrence. — Patuxent FoRMATioisr. Potomac Run, Alum Rock, 

 Virginia. Arundel Formation. Muirkirk (?), Maryland. 



Collection. — TJ. S. ISTational Museum. 



Cycadeospermum rotundatum Fontaine 



Cycadeospermum rotundatum Fontaine, 1890, Mon. U. S. Geol. Survey, vol. 



XV, 1889, p. 271, pi. cxxxvi, fig. 12. 

 Cycadeospervium rotundatum Fontaine, 1893, Proc. U. S. Nat. Museum, vol. 



xvi, p. 279, pi. xliii, fig. 6. 

 Cycadeospermum rotundatum Fontaine, 1899, in Ward, 19tli Ann. Rept. 



U. S. Geol. Survey, pt. ii, p. 667, pi. clxii, fig. 19. 

 Cycadeospermum rotundatum Fontaine, 1906, in Ward, Mon. U. S. Geol. 



Survey, vol. xlviii, 1905, pp. 280, 537. 



Description. — Small, nearly Orbicular nut-like seeds, about 7 mm. in 

 diameter. Surface smooth and hard. 



This species was based originally upon a single specimen found at 

 Kankeys, Virginia, and afterward identified by the original describer 

 from the Glen Rose beds of Texas and from the Oak Creek shales of the 

 Black Hills, which now form a part of Darton's Fuson formation. It 

 is also doubtfully recorded from the Kootanie formation at Great Falls, 

 Montana. 



While these widely removed remains are from nearly the same geo- 

 logical horizon and are identical in appearance, little certainty can be 

 felt as to their actual identity and this for the reason that spheri- 

 cal seed-like remains, which it would be difficult to distinguish from this 

 species, occur at a great variety of geological horizons and might apper- 

 tain to plants of widely differing botanical aifinities. 



Occurrence. — Patuxent Formation. Kankeys, Virginia. Arundel 

 Formation. Contee, Maryland. 



Collection. — U. S. National Museum. 



