﻿42 INTRODUCTORY. 



axial stem or No. i, denoted by e in plates Yii and yiii, early gave rise to the 

 larger branch [a) or No. 2, which is therefore the primary basal branch. Secondly, 

 stem No. 1 gave rise to four basal branches (c, d, 7, f,) three of which are of nearly 

 equal size ; the fourth (marked t) being crowded between two others (d and/), was 

 partially suppressed in its growth. Thirdly, the main branch, that is, stem No. 2, 

 early gave rise to two strong secondary basal branches (b and g). And lastly, the 

 axial stem of the group slowly gave rise to a slightly projecting crown just below 

 its summit, and directly over the position of the partially appressed basal branch (/) 

 mentioned above. As thus closely compacted this branching trunk is a symmet- 

 rical one. The basal view given on plate vin shows well how remarkably complete 

 has been its preservation, and likewise clearly displays the relations and much of 

 the structure of the several parts, as well as their closely set arrangement. The 

 xylem zone of the central and axial stem, as denoted by the letter x in the lower 

 photograph of plate vni, is seen to share in part with that of the largest or first 

 main branch, as a projecting subelliptical ridge, no traces of the roots yet remaining. 

 The comparatively small size of this xylem ellipse will be noted, its long and short 

 diameters being only 16 and n cm. respectively, while the nearly flat base of the 

 group as formed by the central stem and the under surface of the branches growing 

 out from it occupied a ground area of 60 cm. square. Originally the xylem outline 

 must have been nearly circular, but its present strong ellipticity is clearly seen to 

 be due to the early formation of the first main branch or trunk No. 2 of the group, 

 this being the only branch with its xylem extending in so as to share directly in 

 the formation of the base. 



The downwardly directed basal leaf bases of the axial stem are well preserved, 

 as are those of the lateral branches, thus showing that no portions other than the 

 roots are absent; and one can readily see from the position of the leaf crowns of the 

 branches, all of which were evidently in equally active growth, as well as from the 

 configuration of the base of the trunk, as shown in the plate, that the entire plant 

 must have rested quite nearly upon, or certainly not more than 3 or 4 inches beneath, 

 the surface of the ground. 



A close inspection of the present specimen shows that in spite of the profusion 

 of branches, the growth of these was adjusted with the greatest nicety to the space 

 so compactly occupied. The arrangement of the branches for growth in their closely 

 set position being so perfect, the plant in life must have been of exceeding grace and 

 beauty ; hence it is of more than passing interest to note some of the vicissitudes 

 to which this gem of the Mesozoic was subjected after erosion had brought it to 

 view. Originally it had been absolutely perfect ; but Indians or others attracted 

 by its curious form and slight resemblance to the groups of dwarf melon cactus, 

 common in the vicinity, and to which the early settlers of the Black Hills referred 

 the cycads, had slightly damaged the lateral portions of the two main summits, as 

 well as that of one of the larger basal branches. Then three adjacent and connected 

 basal branches made their way to the Yale Museum, receiving the number 164. 

 A year later another shipment of heterogeneous trunks and trunk fragments was 

 received from the Minnekahta locality, and my subsequent examination showed that 

 of these, numbers 143, 267, 281, 285, 392, 411, 224, 240, 256, and 410 were all parts 



