262 WARD 



cially when compared with the giant forms of the Black Hills, I 

 have concluded to call this new genus Cycadella. 



Although a macroscopic examination is sufficient to show this 

 generic distinction, still it does not immediately indicate the true 

 nature of this supplementary envelop. I was at first disposed 

 to think that it consisted of matted leaves. I observed that the 

 leaf bases were always present, filling the scars, and sometimes 

 projecting somewhat above the general surface, and I did not 

 know but that expanded portions of them might have also per- 

 sisted and been rolled and packed against the trunks in the proc- 

 ess of entombment in a manner to produce the observed effect. 

 But a strong glass failed to bring out the difference on the sur- 

 face that would be expected if such had been the case : stria- 

 tions, folds, leaf margins, etc. Moreover, the fractured margins 

 often showed the darker leaf bases coming out to the surface of 

 the true armor, but never continuing across the line of separation 

 and mingling with the tissue of the outer layer, which is some- 

 times more than a centimeter in thickness. 



Since, aside from the reproductive organs, less abundant 

 than in the Cretaceous cycads, the armor consists of nothing 

 else than the leaf bases and the ramentum that is attached to 

 them and constitutes the walls, this last must have furnished the 

 covering which forms the outer coat. It has been observed that 

 these fine scales or hairs are always the most certain to be pre- 

 served, and whatever the degree of imperfection, in the state of 

 preservation in other respects, the walls are usually intact. This 

 accounts for the large number of trunks that consist of these 

 walls penetrated to a great depth by the rhombic or triangular 

 cavities, looking like petrified honeycomb or sponges. This is 

 a most fortunate circumstance, since otherwise we should in 

 such cases have nothing but the woody cylinder of the trunk, 

 and would be entirely incapable of determining the true nature 

 of these objects. 



This special susceptibility to petrifaction on the part of the 

 ramentum explains the presence of the external covering of the 

 Wyoming Jurassic cycads, since it seems actually to consist of 

 a matted mass of these ramentaceous hairs, which in some way 

 developed so luxuriantly upon the sides of the petioles as to push 



