DESCRIPTION OF SPECIES ANTHOZOA 269 



In northern Arkansas the red Saint Joe marble is a widespread forma- 

 tion, occurring at the base of the Boone Chert series with a usual thick- 

 ness of from 25 to 40 feet. 3 This formation is sharply demarked below, 

 but merges gradually into the overlying gray or white cherty limestones, 

 which are the exact equivalent of the Burlington limestone of the Missis- 

 sippi valley. The Saint Joe marble therefore occupies the exact strati- 

 graphic position of the Fern Glen beds of the Mississippi valley ; in litho- 

 logic features also, especially in its color and in the comparative freedom 

 from chert, the two formations are closely similar. In the Mississippi 

 valley, however, there is a much larger content of argillaceous material in 

 the formation, but a hand specimen from the red limestone bed number 2 

 of the typical Fern Glen section is indistinguishable from many similar 

 specimens of the Saint Joe marble from Arkansas. The comparison of 

 the Fern Glen fauna with that of the Saint Joe marble will be considered 

 later, but it may be stated here that some of the most characteristic Fern 

 Glen species occur also in the Saint Joe. The geographic distribution 

 of the Saint Joe marble in Arkansas is chiefly in the valley of the White 

 river and its tributaries, from near Mountain View, Stone county, at 

 about the northern central portion of the state, to the neighborhood of 

 Eureka Springs, Carroll county, in the northwestern portion of the state. 



Description of Species 



fossil localities 



The specimens used in the preparation of the following descriptions of 

 species were collected from the four localities at which the sections are 

 given above, the Fern Glen and Kimmswick localities having furnished 

 the greater number. Most of the specimens used were collected by the 

 writer, but a most valuable addition to them is the collection from Fern 

 Glen made by Mr F. A. Sampson, of Columbia, Missouri. Mr Sampson 

 generously placed his entire collection of Fern Glen material at the dis- 

 posal of the writer for study, and some of the species, notably among the 

 crinoids, have not been met with elsewhere. 



CCELENTERATA 



ANTHOZOA 



CYATHAXONIA ARCUATA n. sp. 



Plate 10, figures 12, 13 



Description. — Corallum cylindrico-conical, curved, becoming regularly 

 straighter toward the larger extremity, pointed below, increasing in 



3 Arkansas Geological Survey; Annual Report of the State Geologist for 1890, vol. 4, 

 p. 254. 



