46 KENTUCKY GEOLOGICAL SURVEY. 



mm. in thickness. Surface smooth; maculae not a prominent 

 feature, often scarcely distinguishable. Apertures small, angu- 

 lar, thin-walled, about 10 in 2 mm. In the immature region 

 the zooecia have thin, somewhat wavy walls and diaphragms 

 from one to three times their diameter apart; in the mature 

 region the walls are thickened and diaphragms are much more 

 closely set> becoming as frequent as two to a tube diameter. 

 Mesopores. few. Acanthopores small, generally few, but some- 

 times each angle of junction is occupied by one. 



Occurrence: This species is found at most localities in Ken- 

 tucky where the Winchester is exposed. The species was first 

 described from material derived from the Catheys limestone in 

 Maury county, Tenn. 



3. From the Eden Group. 



PERONOPORA VERA ULRICH. 



Plate 2, fig. 1. 

 Peronopora vera. Ulrich, American Geologist, vol. 2, p. 40, 1888. 



Zoarium consisting of bilaminar fronds, from 2 to 

 (> mm. thick and 10 or more cm. in height. Fronds 

 usually somewhat undulating and occasionally produc- 

 ing fronds at right angles. Some specimens branch 

 rather frequently, others rarely. Surface smooth, ex- 

 cept for clusters of larger cells which sometimes rise a little 

 above the general level. Apertures circular, 7 or S of the or- 

 dinary size in 2 mm. Apertures in the clusters considerably 

 larger than the others. Usually a large number of circular or 1 

 subangular mesopores o.ccupy the rather wide interspaces as 

 well as the angles of junction. Often the center of a cluster is 

 occupied with a large number of mesopores. In some specimens 

 few mesopores are present. Occasionally a specimen shows a 

 large number of small acanthopores at the surface, and these may 

 also be seen in some sections. Zocecia have a very short imma- 

 ture region; in the mature region they have a linear series of 

 overlapping cystiphragms and a few diaphragms. 



