CORALS OF THE CINCINNATI GROUP. 203 



I have only seen two specimens of this interesting coral, both broken 

 and imperfect as regards the terminations of the branches. In the best 

 of these specimens the entire height, so far as preserved, is one inch and 

 a half, of which the basal cone occupies nine lines. The width at the 

 point where the branches come off is nine lines, and the thickness of the 

 corallum at the same point is five lines. 



This singular form is so remarkable in its shape and mode of growth 

 that I have no hesitation in separating it from all previously recorded 

 species. At the same time its minute characters show no sj^ecial pecu- 

 liarity by which a mere fragment could be distinguished from C. pulchel- 

 lus or C. Fletcheri, E. and H., if we except the fact that the corallites have 

 walls of more than usual thickness when well i^reserved, whilst there is 

 an entire absence of the minute intercalated tubuli so common in the 

 above-mentioned species. The corallum in C. briareus, judging from its 

 sharply pointed and slightly curved base, would appear to have been 

 free, but we have no means of settling this point with absolute certainty. 



The above description is drawn from specimens kindly submitted to 

 me for examination by Mr. U. P. James, of Cincinnati. 



Position and locaUty: Cincinnati group, near Cincinnati, Ohio. 



Chjetetes siGiLLARioiDEs, Nicholsoii. 



Plate 22, figs. 9, 9fl. 



Corallum ramose, of small dichotomously dividing branches, the diam- 

 eter of which is rather over one line. Calices regularly oval or sub-cir- 

 cular, their longer diameter corresponding with that of the stems, 

 arranged in diagonal lines, about six in one line, measured diagonally, 

 and from four to five in the same space, measured vertically. Between 

 the average calices are a few minute sub-cylindrical tubuli. ■ In the cen- 

 ter of each calice, as a, general rule, is a small, circular, secondary calice, 

 about half the diameter of the main calice, and surrounded by a distinct 

 wall, the general appearance of the calices thus somewhat resembling 

 the markings of C. Sigillaria. Walls of the corallites thin. Surface 

 smooth, or with a few low, scattered, and irregular tuberosities, which in 

 no way differ from the general surface, and always form a quite incon- 

 spicuous feature. 



As a general rule, fragments of this species can be recognized with the 

 greatest ease by the peculiar appearance due to the existence of small 

 circular calices within the main calices. In parts of some of the speci- 



