392 Natural History Bulletin. 



about one-half inch in width. A thin rind or bark surrounds 

 the wood}' cylinder and supports the bases of the leaves and 

 leaf structures. Leaves are not known: their bases as pre- 

 served are fusiform or lozenge-shaped in cross-section, half an 

 inch by one inch in dimensions, and show the remains of nu- 

 merous equally developed fibro-vascular bundles. Between 

 the leaf bases are numerous intervals filled up with structures 

 (perhaps pale£e) imperfectly preserved. Where the surface 

 of the fossil is best preserved, the leaf bases appear to have 

 rotted away to a considerable distance inwardly, and the en- 

 tire surface is pitted, and presents a clathrate or reticulate 

 appearance. Rising through the outer conglomeration of 

 tissues, leaf-bases and adhering structures, appear numerous 

 buds (ilower-buds?) ; these are about two inches in diameter 

 and of equal height, attached to the rind by a short C3'lindrical 

 stem, and made up, outwardly, at least, of rather slender, 

 scale-like leaves arranged in circular whorls. 



In habit the plants were solitary or in groups or clusters of 

 two or three apparently from the same base, and sometimes 

 reached much greater dimensions than those recorded — being 

 sometimes at least two feet high. 



The present species is near Bennettites gibsonianus Carr., 

 from which it may be distinguished by greater size and by 

 the fact that in our species the fibro-vascular bundles of the 

 leaf-stems are of uniform size and distribution, and do not 

 form a horse-shoe shape in cross-section as is said to be the 

 case in the English species. 



In Vol. XV, Monographs of the United States Geological 

 Survey, 1889, Mr. W. M. Fontaine records and describes 

 certain Cycad fossils from the Potomac Beds in Maryland. 

 These fossils are referred to a proposed 'genus Tysonia 

 thought to be intermediate between Bennettites Carr., and 

 Mantellia Brongn. I have no doubt but that our Dakota 

 specimens belong to the genus Bennettites, whatever may be 

 the case in reference to the Maryland fossils, although I may 

 be permitted to suggest that these latter also belong to the 



