On the Monticnliporoid Corals of the Cincinnati Group. 3 1 



'I'he species is found in abundance and in great perfection in 

 the vicinity of Cincinnati, and although thousands of fragments 

 have been collected, no single, entire corallum has ever been found. 

 The nearest approach to an entire specimen we have e^'er seen is 

 in the collection of one of us, and it measures from the base to the 

 ends of the branches, five and one-half inches; and across the top 

 at the widest place about the same distance. From its broken con- 

 dition as it lies on the slab it is evident that it grew in a bushy 

 manner and was crushed when fossilized. The specimens as 

 found assume a great variety of shapes, being palmate-digit ite, 

 flabellate, sub-frondose, cylindrical and sometimes amorphous. The 

 upper and outer branches, shown to be such by the calices extend- 

 ing all around and over the ends, are smaller and more delicate. 



The star-shaped monticules differ more on different specimens 

 than do the shapes of the branches themselves. On the upper 

 branches the rays are sometimes elevated into sharp spur-like 

 points, at times extending nearly all around a cylindrical branch ; 

 or they gradually become less and less prominent till they sink to a 

 level with the general surface, or are even depressed beneath it. The 

 number of rays to the different stars varies from five or six to thirty, 

 sometimes appearing like elevated ridges, two or three lines long, 

 the rays formmg spur-like projections on each side and end : others 

 appear like annulations round the branches. The probabilities are 

 that on the base and lower branches of this coral the star varied in 

 shape and prominence from those on the upper parts. 



One of us attempted to describe a new species from specimens 

 bearing depressed stars, but after examining a great number of 

 specimens he found they shaded off so into one another that 

 it was impossible to draw a hne between them, and was not 

 able to find what seemed to be even a constant variety. 



Formation and Locality. — Lower Silurian, Cin. Gr. Cincin- 

 nati, Clermont Co. , etc O., Hudson River Gr-, Delafield, Wise. 



55. M. (CONSTELLARIA ) ANTHELOIDEA, Hall. 



StcUipora antheloidea, Hall. Pal. N. Y., I, 79, 1847. Whitfield, 

 Geol. Wise , IV, 257, 1882. Ulrich, Jour. Cin. S. N. Hist., VI, 

 263, 1883, iyuon Nicholson, Pal Ohio and Pal. Tab. Cor.) 



Corallum thin, parasitic on some foreign object, often a crinoid 

 stem. Surface with star-shaped monticules, each composed of a 

 central, generally depressed area, with from six to twelve elevated, 

 more or less wedge shaped ridges, radiating outwards. Calices 



