LIMESTONE MOUNTAIN AND SHERMAN HILL, MICHIGAN 259 



occur in both layers. A layer similar to the lower one, occurring 

 on Sherman Hill, also carries Decorah fossils but shades up into the 

 heavy dolomite without the intervening thin-bedded layer. The 

 fossils found in the quarry are: 



Crinoid columnals 

 Ceramophylla frondosa 

 Trematopora{?) primigenia 

 Halloporina crenulata 

 Arthrostylus sp. 

 Arthroclema sp. 

 Rhinidictya mutabilis 

 Rhinidictya fidelis{ ?) 

 Arthropora simplex 

 Escharopora suhrecta 

 Escharopora confluens 

 Orthis tricenaria 

 Streptelasma profundum 

 Strophomena incurvata 

 Strophomena septata 

 Dalmanella rogata{ ?) 

 Hormotoma salteri canadensis 

 A par chit es sp. 



Upper Black River {Upper Bluff). — At the extreme southwestern 

 part of Big Limestone and eight feet above the sandstone there 

 occurs a heavy-bedded, cream-colored, fossiliferous layer of dolo- 

 mite. The beds above and below are completely barren, so far as 

 we could determine. 



Ctenodonta nasuta 



Ctenodonta gibberula 



Endodesma{ ?), n. sp. 



Cyriodonta billingsi 



Cyrtodonta cf. billingsi, n. sp. 



Cyriodonta cf. huronensis and subcarinata 



Cyrtodonta cf. tenella 



Cyrtodonta, n. sp. 



Vanuxemia aff. niota Hall and subrotunda Ulrich 



Vanuxemia sp. 



Potsdam (Jacobsville). — This is the lowest horizon in all the 

 outliers and the only stratum which was observed at all three locali- 

 ties. It is a dull-brown, coarse, poorly cemented sandstone with 



