554 PALAEONTOLOGY OF ILLINOIS. 



The name is given in honor of the discoverer, Prof. A. H. 

 Conrad, of Shenandoah, Iowa. 



Position and locality: Upper Coal Measures. Seven miles 

 north of Red Oak, Iowa. 



FENESTELLA IN^QUALIS Ulrich: 



PL LH, figs. 9, 9a. 



Zoarium a strong, irregular, foliar expansion. Branches 

 rather strong, not very straight, sixteen to eighteen in 1 cm.; 

 variable in size on the reverse, where their width varies between 

 0.8 and 0.5 mm.; more equal on the obverse face, where their 

 average width is about 0.4 mm. Dissepiments short, narrowly 

 rounded, of variable thickness, generally less than half the 

 width of the branches. Fenestrules sub-quadrangular or ellipti- 

 cal, unequal, averaging 0.8 by 0.8 mm., and nine in 1 cm. 

 Carina strong but not much elevated, at the summit with a 

 series of closely arranged small nodes, about ten in 1 mm. 

 Zooecia in two ranges, seventeen or eighteen in 5 mm. Aper- 

 tures small, circular, surrounded by an abruptly elevated peri- 

 stome which projects a little beyond the margin of the branch; 

 a fraction less than four to a fenestrule. On the reverse the 

 branches are marked with longitudinal, parallel, granulose 

 striae. The granules are distinct, and so closely arranged that 

 their bases are in contact. When a little worn they disappear, 

 and the surface is thon either smooth or simply striated. The 

 fenestrules have about the same form and are but little, if any, 

 larger than on the obverse side. 



None of the Coal Measure species known to me are as large 

 as this one, nor is any one of them sufficiently like it to re- 

 quire close comparisons. Of Lower Carboniferous species, F. 

 cestriensis and F. compressa are related, but not very closely. 



Position and locality: Upper Coal Measures. Ball's Mill, San- 

 gamon Co., 111. 



