Geology of Upper Illinois. 



153 



were recognized Encrinal stems, a large Spii'ifer, the Pholadomya 

 elongata, (of Morton,) and a species of Producta, of which 

 a figure is annexed, and which I shall denominate the semi- 



Fig. 9. 



punctata. Description. — Length rather surpassing the breadth : 

 slightly inequilateral. Concave valve loith a fold in the middle. 

 Lower valve slightly concave. Hinge-line two thirds the length 

 Vol. XXXIV.— No. 1. 20 



