PLATE A 17. 



Fig. 1. 416. 15. Graptolithus clintonensis. ( Pag. 39.) 



1 a. A lamina of slate, with fragments of this species upon the surface. Where imbedded in the soft green 



sliale, the depth of the serratures and the pointed extremities are not so clearly preserved. 

 1 6. A fragment of a stipe, showing the depth of the serratures and the curvfed extremities. 

 1 c. A similar fragment, showing the opposite side. 



1 d. A small fragment wliich is less flattened, the axis more solid, and the teeth appearing shorter. 

 1 e k 1 f. Enlargements from the previous figure. 

 1 g. A small fragment of the same species, showing some small nodes at the hase of the teeth. 



1 h. A portion ot 1 g enlarged. 



Fig. 2. 417. 16. Graptolithus vexosus. ( Pag. 40.) 



2 a. A piece of slate, with numerous fragments of G. clintonensis and G. venosus. The latter are much more 



indistinct than the former, and can scarcely he brought out without a magnifier. 

 2. b. A fragment of G. venosus enlarged. 



2 c. A fragment (enlarged), which appears to be the upper extremity of the stipe of this species. 

 2 d. A fragment of this species still farther enlarged. 



