46S . Scientific Intelligence. 



ville) as may be seen about Decewville, Ontario. This subsidence 

 was gradual and came in from the east and southeast, while the 

 other progressed northward through the Mississippi embayment. 

 With the beginning of Onondaga time, submergence was rapid 

 and quite general throughout the Mississippian sea. It should 

 be stated here that while the sea on the west of the Cincinnati 

 axis became extinct at the close of the Guelph, on the east in Ohio 

 it continues well into the Cayugan, as is proved by the presence 

 here of Waterlime beds of the age of the lower Manlius of New 

 York. 



A marked peculiarity of the Noblesville assemblage is the 

 almost total absence of corals, although to the south about the 

 Falls of Ohio, and again near the straits of Mackinac, they are 

 present in great variety and abundance. With this exception, 

 the northern Indiana Niagaran fauna is more decidedly that of 

 southern Indiana about the Falls of Ohio than that of northern 

 Illinois and Wisconsin. This is seen by the presence in the 

 Wabash area of the southern forms Anastrophia internascens, 

 Conchidium littoni, C. unguiformis, G-ypidida roemeri, G. nu- 

 cleus, Camarotoechia whitei (= C sp. undet. of K. and B.), C. 

 acinus, Wilsonia saffordi, Atrypa calvini, Sp)irifer foggi, S. 

 radiatus, S. crispus simplex, Cyrtia myrtia, and Meristina recti- 

 rostris. Of strictly northern species, there are in the Wabash 

 area Conchidium multicostatum, Spirifer nobilis, Amphicoelia 

 neglecta, Lituites marshii, Illcenus armatus, I. insignis, I. ioxus, 

 Ceraurus niagarensis, Sphcerexoehus romingeri, and Dcdmanites 

 vigilans. Nearly all of the latter are free forms, with greater 

 powers of dissemination than the brachiopods. These facts seem 

 to warrant the statement that the Wabash axis was already in 

 existence during Noblesville time, and that while it was more or 

 less of a barrier against the free intermigration of the northern 

 and eastern and southern faunas, it was not a complete barrier. 

 That it was not effective is further seen in the peculiar distribu- 

 tion of Conchidium. In the Louisville area during Lockport, or 

 rather Louisville (= Noblesville), time we have C. complanatus, 

 C. crassiplica, C. exponeum. C. knappi, C. littoni, C. nysius, C. 

 tenuicostatum, and C. unguiforme. In central and northern 

 Indiana, about the same time, there are C. colletti, C. littoni, and 

 C. multicostatum, and, in Wisconsin, C. crassiradiatum, C. 

 greenei, and C. multicostatum. During Guelph time, in the 

 Wabash area, there are C. laqueatum and C. trilobatum, and in 

 Wisconsin C. occidentals C. laqueatum is related to C. occiden- 

 tale of the eastern Guelph, while C. trilobatum is unique unless it 

 proves to be a StricMandinia. This indicates that none of the 

 Nobles ville Conchidia pass into the Huntington, but that the 

 species found in the latter formation come from the eastern 

 Guelph. 



That the Wabash axis was in existence long previous to the 

 Niagaran is seen in the distribution of the earlier faunas. The 

 first marked difference in the Ordovician faunas as seen on the 



