A Geological Recoxnoissance. 183 



far as observed, but the softer shales in the upper part of the 

 exposure, on both sides of the river, contain a number of 

 species all ver}- perfectly preserved. The most conspicuous 

 are a spirifer with a divided mesial fold and having a hinge- 

 area narrower than S. -parryana, a ver}^ diminutive Cyrtina 

 hamiltonensis^ a small Athyris vittata^ a ver}'- coarsely ribbed 

 Atrypa retiadaris having the dorsal valve excessively convex, 

 a large form of Strophodonta deviissa, an Orthis impressa of 

 the type O. suhorbictdaris^ ProdticteUa truncata, a small Rhyn- 

 choncUa^ and a Terebratida. Besides the brachiopods we find, 

 though rarely, Alcgistocrimis J'arnszvorthi, and very many 

 specimens of Striatopora ( Cladopora) wzvciisis. 



The following section and explanation was furnished Prof. 

 James Hall at his request, and was published in the Tenth 

 Animal Report of the State Geologist of IVe-w York. It will 

 illustrate the relations of the strata as they are exposed below 

 the mill at Littleton, i, 2 and 3 of this section are the equiv- 

 alent of No. 5 of my paper in American Geologist of Septem- 

 ber, 1 891; 4 and 5 equal 6 of that paper, and 6 and 7 equal 7. 



