500 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



characterized by a mural zone of vesicular tissue, which is not penetrated 

 by the septa. Edwards and Haime say that in P. clevoniense this zone is 

 traversed by the costse, which are not very pronounced, but distinct. This 

 is scarcely apparent in the figure, but, if so, the form represents an inter- 

 mediate stage between P. bouchardi and Pachyphyllum sp., where the thick 

 costae terminate in the mural zone without penetrating it. 



Formation and locality: Three Forks limestone, north side of saddle 

 west of Mount Miller, Absaroka Range ; Louis V. Pirsson. 



CYATHOPHYLLUM Goldfuss, 1826. 



Cyathophyllum C/Espitosum Goldfuss (?) 

 Cyathophyllum ccespitosum Goldfuss, 1826. Petrefacta Germanise, p. 60. 



In the calcareous sandstone, associated with specimens of Actinostroma, 

 Pachyphyllum, Atrypa, etc., is a species of Cyathophyllum, which may be 

 identical with G. ccespitosum Groldf. It consists of isolated fragments of 

 cylindrical corallites, which have about forty alternately long and short 

 septa, a tabulate central portion, and a vesicular outer zone. In size, general 

 character, and in specific detail, as far as determinable, these strongly 

 resemble Goldfuss's species, and may, like it, when entire, have grown in 

 tuftlike masses. Indeed, the small diameter and the cylindrical form 

 of the corallites are favorable to such an interpretation. C. ccespitosum is 

 already known to occur in American strata, being found in Upper Helder- 

 berg rocks. 



Formation and locality: Three Forks limestone, near the divide between 

 Gallatin Valley and Panther Creek; Bighorn Pass, Gallatin Range, bed 21; 

 S. L. Penfield. East slope of Antler Peak, Gallatin Range; H. C. Gill. 

 North side of saddle west of Mount Miller, Absaroka Range; Louis V. 

 Pirsson. 



CLADOPORA Hall, 1852. 



Cladopora sp. 



Like the other corals from the same bed, specimens ol Cladopora are 

 coarsely silicified and considerably weathered. The branches are circular, 

 and about 5 mm. in diameter. The pores are nearly circular, small (about 

 0.25 mm. in diameter), and separated from each other by a distance about 



