KENTUCKY GEOLOGICAL SURVEY. 43 



2. From the Winchester Group. 



ERTDOTRYPA BRIAREUS (NICHOLSON). 



Plate 1, figs. 4, 5. 



Zoarium a branching stock from a pointed base; branches 

 smooth, cylindrical, from 3 to 8 mm. in diameter, and given off 

 at an acute angle. Apertures oval, rather thick-walled, usually 

 oblique to the surface, about 7 in 2 mm. Apertures of rather 

 larger size occur in clusters which are not raised above the gen- 

 eral surface level. Zooecia thin-walled and polygonal in the 

 axial region; walls thickened in the peripheral region. Dia- 

 phragms present, particularly in the transition zone, i. e. where 

 the zooecia change from the immature to the mature state. 

 Few mesopores and no acanthopores developed. 



Occurrence : A common and characteristic form of the Win- 

 chester group. The original specimen, from which Professor 

 Nicholson drew up his description and which is rather excep- 

 tional in the large number of branches it developed in a short 

 space, came from the river bank at Covington. Ky. The species 

 occurs abundantly at Covington, Moscow, Falmouth, Lair, Pleas- 

 ant Valley, Winchester and Lexington, Ky., and at Point Pleas- 

 ant, Ohio. The pointed base distinguishes it at once from as- 

 sociated forms. The branches may be known by their smooth 



surface and the commonly oblique apertures. 



/ 



PERONOPORA MILLERI N. SP. 



Plate 1, fig. 6. 



Zoarium consisting of bifoliate, flat or undulated fronds, 

 varying from 1 to 3 mm. in thickness; height and breadth un- 

 known as only incomplete examples have been found, which 

 measure several cm. in height and breadth. Occasionally 

 branches which are themselves bifoliate fronds, grow at right 

 angles to the parent frond, and in like manner from these 

 branches others may grow. Surface smooth; the clusters of 

 slightly larger apertures scarcely raised above the general level. 



