PLATE A 17. 



Fif. 1. 416. 15. Gr.'Vptolithus clintonensis. ( Pag. 39.) 



1 o. A laniinA of s^ato, with fragments of this speciis upon the surface. Where imbedded in the soft green 



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

 I b. A fragment of a stipe, showing the depth of the serratures and the currtd extremities. 

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



1 d. A small fragment which is le.ss flattened, the axis more solid, and the teeth appearing shorter. 

 1 e & 1 /. Enlargements from the previous figure. 

 I g. A sn)all fragment of the .same species, showing some small nodes at the hase of the teeth. 



1 ft. X portion of 1 g enlarged. 



I'ig. 2. 417. 16. Graptolithi's ve.nosus. ( Pag. 40.) 



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



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

 2 6. A fragment of G. venusus enlarged. 



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

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



