710 



Report of the State Geologist. 



piece and exhibits on the latter a cross of four ridges, consisting of pyrite. A 

 similar aspect is presented by the node in the middle of the basal appendage 

 of figure 1 7, Plate III, which is an enlargement of the base of the specimen 

 reproduced on Plate I, figure 1, and which shows two arms and the intersec- 

 tions of the two others on top of the central node. The pyrite in both specimens 

 points to the former existence of canals, or at least to an original difference 

 between the material which has been replaced by pyrite' and the enclosing 

 chitine. There can hardly be any doubt that the cross of pyrite represents 

 the basal junction of the marginal grooves of the pyramid, and that the little 

 node in the center of the base (cf. figs. 11 and 17, PI. Ill) is the real apex of 

 the pyramid. The direct continuance of at least two grooves is exhibited 

 by quite a number of remains, e. <j., by those reproduced in figures IS and 19, 

 while the original to figure 20 gives a neat section through the four grooves 

 at the entrance of the pyramid into the bell. It is evident from the latter 

 fossil that these grooves, as already demonstrated, were originally covered by 

 a carbonaceous film and filled with phosphate of lime. The supposition is, 

 therefore, not out of the way, that they may have been free from this filling 

 towards their proximal ends and could therefore have been filled by pyrite 

 during the process of fossilization. 



The morphology of the whole appendage will be best understood from a 

 diagrammatic section, as given in figure 21, Plate III. The apex of the pyra- 

 mid (7/) is enclosed in a stout central cup (ti) which, in turn, is connected by 

 a thin film (c) with the broad basal extension of the exterior bell The 

 latter again is fastened to the pyramid a little above the cup. 



There can be no doubt that the basal appendage was an organ of 

 attachment. It is further evident that the latter did not amount to a 

 coalescence, but was of a temporal'}' character only ; for the not uncommon 

 occurrence of detached specimens with well-preserved basal appendages (cf. 

 figs. 2 and 4) is not consistent with the assumption of a coalescence. The 

 apparatus, therefore, can not be compared to the basal disks, such as certain 

 bryozoans have. On the other hand, it is indicated by the impressions left 

 by the appendages* that their inner parts were ilexible or even retractible 

 while the stout exterior bell, with its broad, radially striated base, apparently 

 served to give stability to the mechanism and to close the interior tightly 

 from the exterior. 



An attempt to compare the basal appendages to suckers, such as various 

 gastropods use for purposes of attachment, would lead to the further 



* Cf. figs. 9 and 16, which show the ring- like impression (c) of the bell to be considerably deeper than that of the wrinkled 

 basal film (d). 



