Fauna L Considerations. 



An extremely interestiug fauna has been disclosed along the line of the 

 general section. It embraces some fifty genera, and between one hundred 

 and fifty and two hundred species. A part of these have already been 

 studied and full annotations made ;* another part has also been critically 

 examined, and the results will soon be announced; while the remainder will 

 be subsequently considered. The special significance of these fossils lies : 

 (1) in the great profusion of minute molluscan shells; (2) in the occurrence 

 of a large number of species hitherto unknown within the limits of the 

 state ; and (3) in the presence of many forms which have been known from 

 a few only or even single specimens, and from localities widely separated 

 geographically. The peculiarities of the fauna alluded to are so striking 

 and the biological and geological relations so important in their bearing on 

 the geographic distribution of organisms during Carboniferous times, that 

 a list of the species thus far identified is appended. Besides those mentioned, 

 there are a considerable number of additional forms whose specific identity 

 has not as yet been determined with sufficient accuracy to warrant incorpo- 

 ration in the present list. 



Fossils from the Lower Coal Measures of Central Iowa. 



PROTOZOA. 



FuBulina cylindrica, Fisher. 



CCELENTERATA. 



Lophophyllum proliferum, McChesuey. 

 Mhombopora lepidodendroides, Meek. 



E CHINODERMA TA . 



Arclimocidaris edgarensis, Worthen and Miller. 

 EupachyGrinus, sp. und. 



MOLLVSCOIDEA. 



Synocladia hiserialis. Swallow. 



Discina 7iitida, Phillips. 



Frod actus nanus, Meek and Worthen. 



" cora, d'Orbigny. 



" muricatus, Norwood and Pratten. 



Proc. Acad. Nat. Sci., Phila., 1888,'pp. 222-2JG. 



(288) 



