If we go from the known to the nearest unknown we shall 

 study these forms in the descending order, thus reaching first 

 the one nearest, 5". rugostim, in horizon and age. 



It may assist just here to recall that in many localities the 

 Chazy rocks may be helpfully distributed into three divisions, 

 these A, B, C, reading from below upwards. 



In division C Chazy there are strata that have been known as 

 Upper Dove. In some localities this mass is notable for a 

 wonderful display of the remains of cephalopods. With these 

 cephalopods or just beneath them on Isle La Motte is found a 

 Strowatoceriitni having for its own a distinct and peculiar 

 character widely different from that of the typical species. 



The fossil appears mostly in the form of sheets two to four 

 inches in thickness accommodating itself to the varying surface 

 of the underlying rock. In color it is light, in texture tough, 

 yet on weathering, it breaks away into detached plates. The 

 laminae are slightly rugose, thin, closely set, rather easily de- 

 tachable from each other, on the upper surface are mostly in 

 concentric circles or ringed about eye like points of varying 

 size. 



The early collections were made by the assistance of Pro- 

 fessor W. W. Eaton. 



The form may be appropriately distinguished by the name 



Stromatocerium Eatoni. n. sp. 

 PI. LXXI, PI. LXXIV, fig. 2. 



A stromatoceroid fossil occurring in sheets two or more 

 inches in thickness; the upper surface usually covered with con- 

 centric rings, circling around elevations or eyelike points, 

 laminae thin, scarcely rugose. 



The tabulate mass and upper concentric laminae widely dis- 

 tinguish the species from 6". rugosiim. 



Horizon. C Chazy. 



Locality. Isle La Motte, Vt. Goodell's Ridge, south of 

 Village. 



Leaving this interesting horizon and going south and geologi- 

 cally down, B Chazy is reached. In this mass of rock that has 



