CRINOID GENUS SCYPHOCRINUS 1 3 



original condition, and little altered by chemical or other action, except in the 

 way of silicifkation and the filling of the cavities with solid matter. A repre- 

 sentative series was selected ranging from 25 to no mm. diameter, all with the 

 stem attachment and roots ramifying downward into the spheroidal mass, 

 surrounded by the peculiar projecting collar mentioned by Schuchert. 1 



Except when adhering to them by growth, no other remains of Scypho- 

 crinus or other crinoids were found associated with these bulbs. To some of 

 them are attached bryozoa, small brachiopods, the base of a small species of 

 Edriocrinus, and certain roots representing young stages of the Camarocrinus 

 hereinafter described; these are usually confined to mature specimens. In 

 others the surface is free from foreign organisms, being entirely composed of 

 irregular, polygonal plates, as illustrated by Schuchert in his plate 40. Such 

 individuals had probably been completely buried in the mud. The important 

 fact in this connection is that no other remains of this large colony of adult 

 crinoids were to be found in the deposit. It is thus evident that the crown and 

 stems belonging to them had been swept away, leaving the bulbous roots 

 imbedded in, attached to, or resting upon the mud, where their cavities became 

 filled with matrix and solidified by infiltration of mineral solutions. Contact 

 with the sea bottom might in many cases have been by a small area, leaving 

 much space for attachment of bryozoa and other adhering forms ; and no doubt 

 some of the bulbs became dislodged by various agencies. The mode of occur- 

 rence at this locality is about the same as that described by Schuchert (op. cit., 

 p. 263) for the occurrences in Oklahoma, as is shown by a large collection from 

 that field in the National Museum. 



There are other Camarocrinus horizons in this region, as stated by Foerste, 

 and in these the bulbs are associated with the calices and stem fragments of 

 Scyphocrinus, usually in hard or cherty limestone, with occasional partings or 

 pockets filled with clay. Many of the remains in these beds are much disturbed, 

 broken, and intermingled. The bulbs are often crushed, some adherent to 

 calices (PI. VII, figs. 20, b) ; and both more or less encrusted with bryozoa — 

 showing that the organisms had been washed out of their original bed and 

 moved about upon the sea bottom before final deposition in the limestone 

 sediment. Some of the bulbs in this condition are geodized, and lined with 

 quartz and calcite crystals. No crowns were found intact, and in only a single 

 instance was any part of the arms preserved. 



At five localities the calices occurred in considerable numbers, belonging 

 chiefly to two extremely well-marked species heretofore unrecognized in the 

 genus, and strikingly different from those of the Scyphocrinus elegans type. 

 These are the S. pratteni of McChesney, described from an imperfect calyx, 

 whose important characters have not heretofore been understood; and a fine 



'Op. cit, p. 263, pi. 41, fig. 1. 



