FOSSIL CYCADS FROM THE BLACK HILLS— WARD. 217 



the leaf scars, whose shape and order they distort, elliptical in outline, 

 25 to 40 mm. in a horizontal and 38 to 20 mm. in a vertical direction, 

 surrounded by concentrically arranged semilunar or somewhat tri- 

 angular bract scars which are sometimes continued in a horizontal 

 direction, converging and blending with the rows dividing the walls, 

 the central portion when exposed at the margin of a fractni-e taking 

 the form of an eloiigated cylindrical spadix or fruit, which, seen in 

 cross section, proves to l)e made up of four large organs which seem to 

 contain two axes, and seen in longitudinal section, to constitute a con- 

 vex receptacle from which arise seminiferous peduncles (or filaments) 

 and interseminal (or interstamiuate) scales, the seeds (or anthers) 

 having disappeared leaving a region of amorphous decayed tissue 

 occujned by the matted prolongations of the chatt'; armor 8 to 9 cm. 

 thick; liber zone very indistinct; cortical parenchyma 3 to 4 cm. thick; 

 fibrovascular zone about 2 cm., without visible subdivision into rings; 

 medulla slightly elliptical, the major diameter 10 to 17 cm., the minor 

 ]3 to 14 cm., black and cherty in all the specimens, showing no structure, 

 giving oft' rays which may be seen traversing the woody cylinder. 



The above description is based mainly on two large trunks, or i)arts 

 of the same trunk, which, through the intervention of Professor -lenney, 

 were generously loaned to the Smithsonian Institution by Dr. Y. T. 

 McGillicuddy, director of the State- School of Mines of South Dakota 

 in Kapid City, where they had been deposited. There are numy rea- 

 sons for believing that these two pieces belong together, and, with a 

 small missing intermediary piece, constituted a tall, cylindrical trunk. 

 One of the pieces, about 40 cm. long, represents the true base, and the 

 other, 58 cm. long, the true summit. The former is scarcely worn at all, 

 while the latter is deeply eroded all round as the result of having been 

 long exposed to adverse intluences, probably by having lain in the bot- 

 tom of a gulch. It is therefore considerably smaller than the normal 

 diminution upward would require. The ditterence applies, however, 

 wholly to the exterior, and the medulla and woody cylinder are no 

 smaller than would be the case in an entire trunk at different heights. 

 After a careful examiiuition I have arrived at the conclusion that if 

 they are parts of one trunk it would only indicate the loss of about 

 30 cm., which would give a total height for the trunk of about 130 cm. 



Only two other tall, cylindrical species of Oy(;adeoidea are known to 

 me, namely, the C. e.reelm, described below, and the C. {/igantea of 

 Seward from the Purbeck beds of Portland.' Specifically, of course, 

 C. jenneyand is very distinct from both of these, but in its sti-aight, 

 erect habit it somewhat resembles G. (jUjantea. It is nuich less com- 

 pressed laterally, and if my conclusions are correct as to the amount 

 missing between the two sections, it was taller by 11 or 12 cm. Mr. 



'A. C. Seward, on Cycadeoidea (jiciantea, ii new Cycadean stem from tlie rur))eck 

 beds of Portland. Quart. Jouru. Geol. Soc. Loudon, February, 1897, LIII, pp. 22-39, 

 pis. i-v. 



