The Stromatoceria of Isle La Motte, Vermont, 



Bv H. M. Seelv, Middlebury, Vt. 



A preface and a help to the study of the various forms of 

 Stromatoceria in the divisions of the Chazy rocks will be 

 found in a fresh reading of Professor James Hall's description 

 of the genus and the typical species. The essential portions 

 of the description are here reproduced. Reference is especially 

 made to Hall's Pal. N. Y., Vol. I, Page 48, and Plate XII. 



"GENUS STROMATOCERIUM.' ' 



"In the black marble of Isle La Motte, and in the same rock 

 at Chazy but particularly in the dark limestone containing 

 Coliimnaria we find numerous specimens of obscure corals hav- 

 ing a structure represented in figures (given). They are com- 

 pletely silicified so that the more minute structure cannot be 

 decided; but since they are abundant and require notice I have 

 proposed the provisional name Siro/natoceriuiit, from Stroma, 

 a layer, or lamina, and Kari'on, honeycomb." 



"Stkomatocerium rugosum." 

 PI. LXX, PI. LXXIV, fig. 5. 



"Coral hemispherical; growth in concentric laminae or 

 strata; laminae, numerous, wrinkled; some faint indications of 

 vertical tubes or cells. 



"This coral usually appears as a rough, shapeless excres- 

 cence upon the surface of the limestone; but a little examina- 

 tion shows it to be composed of concentric layers w^hich are 

 evidently the skeleton of some coral. 



"Position and locality. This coral as far as is known is con- 

 fined to the Black River limestone. * * * It occurs in the 

 dark marble quarried on the east side of Isle La Motte. But 



