508 



Report of the State Geologist. 





Figs. 51-53. Hemitrypa columellata. 



Fig. 51. A transverse section of a frond, xl8. 



Fig. 52. A side view of a portion of a branch and its carina, xl8. 



Fig. 53, Showing the tubular appearance of a transverse section of the carinas and scalae. 



Unitkypa, Hal]. 

 (Rep. of K Y. State Geologist for 1884, p. 36. 1885.) 

 Type, Unitrypa lata, Hall. 



(Plate 5, figs. 15-19; PI. 6, figs. 1-6.) 

 Fronds having the general appearance and mode of growth of 

 Fenestella. The cell apertures are arranged in two parallel 

 rows, separated by a carina ; carina prominent, thickened above 

 and connected by thin oblique plates (scalae). Frequently the 

 scalee are abruptly bent at about half their height, and always 

 present an imbricated appearance. 



\. (_Ws'„H 



Fig. 54. Unitrypa fastigata. An enlargement showing the side view of a branch, with its carira, 

 and section of the scalse. The scalse are oblique toward the base of the frond, a mode of growth of 

 rare occurrence. 



Fig.' 55. U. lata. A side view of a branch and its carina, and a section of the scalae, xl8. 



