Descrijjtion. — Elongate, turbinate, more or less curved, the basal one 

 or two inches slender, then rapidly expanding to a diameter of from one 

 to four inches, then becoming cylindrical. The form is that of a large 

 Cyatlioi^hyllum or Zaphrentis. The cavity of the cup extends in depth 

 nearly to the base. The radiating septa are thin and closely crowded 

 together, there being eight or ten in the width of three lines. The 

 surface is annulated by strong rough ridges from three to six lines distant 

 from each other, the intervening furrows being two or three lines deep. 

 The inner wall of the cup is exceedingly thin, apparently less than half a line. 



In none of the specimens is the outer wall preserved except in spots, 

 and there only partially. The large individuals appear to have attained 

 a length of more than one foot with a diameter of from two to four inches. 



In 1861 I referred this species to A. 3Imganensis, but further exami- 

 nation induces me to regard it as distinct. The latter is more deeply 

 and distantly annulated, and, besides, it occurs in a higher geological 

 position than does the former, having been found only in the Calciferous 

 formation. 



Locality and Formation, — Anse au Loup, on the north shore of the 

 Straits of Belle Isle ; limestone of the Potsdam group. 



Collector. — J. Richardson. 



Archeocyathus Atlanticus. (N. sp.) 



Fig. 5. 



Fig. 5. — a, a fragment of this species ; &, a transverse section ; c, a longitudinal section 

 of the same. 



