324 CABBONIFEROirS FORMATIONS AND FAUNAS OK (lOLORADO. 



study. As these agree, in all the points mentioned b}' White in his description, 

 with 7j. gibsoni, I have referred them to that specie^ without much hesitation. 



Locality and horizon. — San Juan region (stations 2216, 2332); middle and upper 

 Hermosa. Crested Butte district (station 2312); "Weber limestone. 



MONILU:'ORA Nicholson and Etheridge, 1879. 

 MoNiLiPOEA PKOSSERi Beede. 



1898. Aidopora prosseri. Beede, Kansas Univ. Quart., vol. 7, No. 1, p. 18. 



Upper Coal Measures: Lyndon, Osage County, Kans. 

 1900. A uloporn'? prosseri. Beede, Univ. Geol. Surv. Kansas, Eept., vol. 6, p. 23, pi. 3, fig. 2; pi. 4, fig. 2. 



Upper Coal Measures: Lyndon, Osage County; Lecompton and near Twin Mounds, Douglas 

 County, Kans. 



This form occux's in large masses in some thin limestones outcropping along the 

 Silverton road in the Engineer Mountain quadrangle (station 2199). It agrees in so 

 man J' particulars with Auloporaf prosset'i, as the latter is represented in Beede's 

 illustrations and descriptions, that it probably belongs to the same species. 



Beede calls attention to the large size to which coralla of this species sometimes 

 attain, citing one colony which, though incomplete, measured 22 inches across. At 

 the Colorado localitj' a growth, belonging apparently to a single colony, formed a bed 

 from 3 to 6 inches high, which covered an area of 9 square feet and probably consid- 

 erably more. While the size of the colony in these instances is suggestive rather of 

 the genus Syringopora, the manner of growth is different, for instead of consisting of 

 long, nearly parallel corallites connected by stolonal arms, the individuals are short 

 and variously directed. They bud persistently, and I judge, although the imperfect 

 manner in which the specimen is seen embedded in matrix may be misleading, that 

 with few exception each corallite gave off two buds at a time, and perhaps more than 

 once. There results a thick entanglement of corallites pointed in various directions; 

 and though the component units are short and not connected and supported by 

 stolonal growths, as in Syringopora^ they contrive to build up a colony, as has been 

 said, of several inches in height and very great spread. They are no doubt enabled 

 to do this through the circumstance that the cell walls are excessively thickened, 

 so that the lower portion of the corallites are nearlj^, possibly entirelj', closed in 

 this manner. It is naturally by concentric deposition that the walls are thickened; 

 and as all the layers are not of quite the same consistency, weathered specimens 

 sometimes present an appearance which simulates the well-known internal structure 

 of Syringopora, but here the lines which might be mistaken for infundibuliform 

 tabulsB are invariably completely circular, which is rarely the case in Syringopora., 

 and the J' are parallel to the walls instead of converging to the center. The real 

 structure, as unmistakably shown in thin sections, is with the inner space, though 



