298 Clara Gould Mark 



Orthothetes crassus (Meek and Hayden) 

 Chonetes mesolohus Norwood and Pratten 

 Productus semireticulatus (Martin) 

 Productus cor a rf'Orbigny 

 Productus longispinus Sowerby 

 Spirifer caniaratus Morton 

 Spirifer rockymontanus Marcou 

 Reticularia perplexa (McChesney) 

 Seminula argentea (Shepard) 



Zeocrinus sp. 

 Crinoid segments. 



The Mercer limestone in the Fultonham region consists usually 

 of a single hard compact layer of a dark blue color. In one or 

 two places it is divided into two layers, but these are in contact 

 without shale or other material separating them. A layer of iron 

 ore is often found lying immediately upon the top of the limestone, 

 which upon weathering gives it a very irregular upper surface. 

 The limestone does not weather shaly as it does in the Bald Hill 

 and Flint Ridge regions, but breaks out in large rectangular blocks 

 which retain their shape when weathered. In the older valleys 

 and along the hillsides where the other members of the Pottsville 

 and Allegheny formations have been covered with soil and vege- 

 tation the limestone blocks are often quite conspicuous and mark 

 the horizon of the Mercer. This is particularly true in the open 

 fields to the south and west of the village, and along Bush creek 

 toward Somerset. It is a noticeable fact that, whereas in the 

 gullies formed by the younger streams the Homewood sandstone 

 is the conspicuous member exposed, often forming cliffs along the 

 valley walls while the lower members of the Pottsville formation 

 and those of the Allegheny formation above are frequently covered 

 with soil, in the older valleys the Mercer limestone is the member 

 left exposed after all the others are covered. 



The fauna of the limestone in this region differs somewhat from 

 that of the exposures at Bald Knob and Flint Ridge, the principal 

 difference being in the almost complete absence of the small 

 pelecypods so abundant in those localities. The gray calcareous 



