Species. 87 



Lower Cretaceous strata, valley of Minnekahta Creek near Minnekahta 

 Station of the Burlington and Missouri Railroad, Fall River County, South 

 Dakota (Black Hills). 



Cycadeoidea Jenneyana n. sp. 



Trunks cylindrical-conical, 15 to 17 inches in diameter and 2 to 3 feet high 

 with concave depression ("crow's nest") at the summit; cross section of 

 leaf stalks very irregular, rhombic or trapezoidal, two of the angles often 

 very acute or prolonged indicating wings, the other angles obtuse. 



Divide between Box Elder Creek and Elk Creek, six or eight miles north 

 of Rapid City, South Dakota (Black Hills). Formation not yet determined 

 but probab'y same as lust. 



The above desci-iption and data as to location are taken from letters re- 

 ceived from Prof. W. P. Jenney, Dean of the Faculty of the State School of 

 Mmes at Rapid City where the specimens now are. There are two specimens, 

 one of which shows the summit but lacks the basal portion and is 21 inches 

 high and 15 inches in diameter at the lower end. The other shows the base 

 but not the summit, is 17 inches in diameter and quite cylindrical, but 

 truncated at the height of 16 inches. This form clearly indicates that the 

 species at least is distinct from the last and it is possible that when betfer 

 material is discovered it may require to be referred to some of the less 

 dwarfted genera, such as Bucklandia or Cylindropodium. The distinction 

 is further emphasized by the difference in the shape of the leaf bases or 

 perforations left by their disappearance. 1 have named the species for 

 Professor Jenney to whose assistance I am so greatly indebted in determin- 

 ing the geological position of the fossil plant beds in the southern portion of 

 the Cretaceous rim of the Black Hills, a region which scientifically he has 

 made his own. 



Cycadeoidea Abequidensis Dawson. 



1871. Cycadeoidea Abequidensis Dawson, Geol. Struct. Prince Edward 

 Island, p. 45, pi. iii, fig. 29. 

 Trias of (Tallas Point, Prince Edward Island. Sir Wm. Dawson referred 

 this deposit doubtfully to the Lower Triiis, but some regard it as the equiva- 

 lent of the Newark Svstem. 



