GEOLOGY OF THE FOURTH DISTRICT. 



ORGANIC REMAINS OF THE CLINTON GROUT. 



No. 4. — No. 14, page 60. 



Fucoides gracilis, H. One of the most persistent and common fossils of the group. 



No. 5. — No. 15, page 70 of Report. 



Figs. 1, 2 and 3. Pentamerus oblongus. 1. The large variety, somewhat three-lobcd. 2. A 

 more circular form of the same shell. 3. A side view of a specimen intermedi- 

 ate in form to the other two. Rochester. 



Fig. 4. Cast of upper valve of same fossil. 



Fig. 5. Cast of lower valve. 



Fig. 6. Delthyris brachynota, H. Reynolds's Basin, Niagara county. 



No. G. — No. 10, page 71. 



Fig. 1. Orthis circuits, H. Two \iews — a beautiful striated circular shell, with a very 

 small area. Reynolds's Basin, Niagara county. 



Fig. 2. Atrypa congesta, C. (Jour. Acad. Nat. Sci. Vol. 8, page 265, plate 16, fig. 18.) Shell 

 striated concentrically, and not with radiating lines as the figure would indicate. 



Fig. 3. Atrypa naviformis, H. A nearly smooth shell, somewhat concentrically striated, and 

 with a few more prominent lines of growth. (Compare Atrypa linguifera — Si- 

 lurian Researches, pi. 13, fig. 8.) Sodus Point. 



Fig. 4. Atrypa plicatula, H. A small plicated shell, with three of the folds raised in front. 

 Reynolds's Basin, Niagara county. 



Fig. 5. Crinoidal joint, natural size and magnified. A widely distributed fossil, being known 

 abundantly in New- York and Ohio. 



