May, VMt] Silurian Fossils from Ohio 241 



According to the well record presented by E. P. Cubberley, 

 on page 241 of the Eighteenth Annual Report of the Geological 

 Survey of Indiana, cited above, the thickness of Silurian rock 

 underlying Muncie, Indiana, is 265 feet. This would place the 

 clay shale in the Muncie quarry, containing the recurrence of 

 the Waldron fauna, about 220 feet above the base of the Silurian. 

 Considering the fact that at St. Paul, in the northwestern part of 

 Decatur County, Indiana, the thickness of the Laurel limestone, 

 which directly underlies the true Waldron shale, is 50 feet ; that 

 of the underlying Osgood formation, about 8 feet, and that of 

 the Brassfield limestone, if present at all, certainly not more 

 than 20 or 30 feet as the extreme, it is impossible to regard the 

 clay shale layer in the Muncie quarry as identical with the 

 Waldron shale of the more southern parts of Indiana, although 

 evidently containing a recurrence of the Waldron fauna. In 

 fact, it is possible that the fauna exposed in the quarry at 

 Muncie belongs stratigraphically above any Niagaran strata 

 included in the Louisville limestone in southern Indiana, and 

 also above any Niagaran strata referred to the Cedarville 

 dolomite in western Ohio. 



Several facts suggest that the clay shale horizon in the 

 Muncie quarry is of later age than the typical Waldron shale. 

 The entire thickness of rock exposed beneath it is massive, 

 without well marked bedding planes, and is strongly dolomitic. 

 Moreover, Phanerotrema occidens so far has not been found 

 below the level of the Louisville limestone and Cedarville 

 dolomite. 



The rock immediately above the clay shale horizon in the 

 Muncie quarry, for a thickness of 25 feet, is very porous and 

 massive, strongly resembling the Cedarville dolomite of Ohio 

 lithologically. It contains a Fistulipora resembling Fistulipora 

 neglecta-maculata in general appearance, also a species of 

 Conchidium, Dalmanites verrucosus , and the unnamed species of 

 Bumastiis from northern Indiana described by Kindle under 

 IllcEnus insignis. 



Above the massive, very porous rock, in the Muncie quarry, 

 there is a series of thin bedded limestone, the individual layers 

 of which are 3 to 4 inches thick, the total of the layers exposed 

 equalling 12 feet. This is the richly fossiliferous part of the 

 exposures at Muncie. It is best exposed, for purposes of 

 collecting, directly east of the quarry, on the opposite side of the 



