MARCELLUS LIMESTONES AND THEIR FAUNAS 117 



at that date, neither, in its character, extent and faunal con- 

 tents, has been fully exploited till lately, nor has the interest- 

 ing fact been sufficiently emphasized that both carry compara- 

 tively profuse faunas fundamentally unlike each other but evi- 

 dentty derived from the same direction, and quite unlike the 

 normal fauna of bituminous shales. 



STRATIGRAPHY OF THE AGONIATITE LIMESTONE 



Madison and Onondaga counties 



For the most part the outcrops of this rock in Madison and 

 Onondaga counties are obscured by the soil mantle or, where 

 seen in drainage sections, are of partial thickness and fail to 

 disclose the actual relation of the beds to the involving shales 1 . 



There are several such small outcrops in the vicinity of 

 Manlius. For example, the rock appears on the road from Eagle 

 village to Chittenango not far from a schoolhouse at which a 

 road turns north, about -J mile west of the west line of Madison 

 county; and again about J of a mile southwest of Eagle village 

 in a small ravine. In another little ravine near the schoolhouse 

 in district 8, southwest corner of the town of Manlius and about 

 li miles west of the village on the road to Jamesville, the lime- 

 stone forms the sill of a cascade, being in two layers, the upper 

 about 1 foot thick and the lower nearly 2 feet. So great a 

 thickness is rarely shown by the formation. The rock is hard 

 and compact, specially at its contact above and below with the 

 shales, and the characteristic large cephalopods (Agonia- 

 t i t e s expau s us, O r t h oceras marcellense, etc.) of 

 the formation are mainly in the lower part of the upper layer. 

 About 100 rods farther west another small brook crosses the 

 Jamesville road just at the intersection of a north and south road. 

 Here the Onondaga limestone is considerably flexed, and over it 

 lies a slight exposure in the bed of the creek and on the south 

 bank. None of these exposures has afforded opportunity for an 

 accurate measurement of the thickness of the Marcellus shales 

 above and below the limestone. 



1 The sections in this region and in Cayuga and Ontario counties have at my request recently 

 been reviewed by D. D. Luther, who has supplied much of the detail hero given. 



