CAMBRO-SILURIAN MICRO-rALiEONTOLOCir. 15 



Polerboro', ODtario," and '* common (the 'puff-ball variety') in the 

 Hudson Eivcr group of Toronto, Weston, and other localities in Ontario." 

 It has now to bo recorded from the Chazy Formation of the Island of 

 Montreal, an individual in the Museum of the Geological and Natural 

 History Survey, having been identified with this species. 

 Collector. — E. Billings. 



MONOTRYPELLA, Ulrich. 



"Ivamosc, smooth or tuberculated. Cells apparently of one kind onlj^. 

 ^yalls very thin in the axial portion of the branches, but much thicker in 

 the peripheral region. Diaphragms straight. Ko spiniform tubuli. 

 Trenton and Cincinnati." (B. 0, Ulrich, Journ. Cincinnati Soc. Nat. 

 Hist, Yol. v., p. 153, 18S2.) 



MoNOTRYPELLA Trentonensis, Nicholson, Sp. 



Moniicuh'pora iHeterotryj^a) Trentonensis, Nicholson. "The genus Monticuli- 

 pora," p, 149, fig. 28, 1881. 



Locality and Formation»-^Di\ Nicholson records this species as ^' abun- 

 dant in the Trenton Limestone of Poterboro', Ontario." It covers large 

 surfaces of the strata in the Trenton Formation in and around Ottawa 

 City, and is common throughout this formation in Canada. It is difficult 

 to distinguish this species from Ilomotrypa simills, Foord, by its external 

 characters alone, and microscopic sections are necessary in order to 

 separate the two species with certainty. The specimen figured by Billings 

 in the "Geology of Canada " (p. 156, fig. 116, 1863), as Stenojwra fibrosa, 

 Goldfuss, should probably be referred to Monotrypella Trentonensis. 



Collectors,— ^\v W. E. Logan, W. E. Billings, H. M. Ami, A. II. Foord. 



Monotrypella ^equalis, Ulrich. 



Monotrypella wqualisj Ulrich, Journ. Cincinnati Soc. Nat. Ilist., p. 247, plate 

 XL, figs. 3, 3aj 3b, 1882, 



Locality and Formation. — Not uncommon in the Black River Formation 

 at Paquette's Rapids, on the Ottawa River. 



Collector. — J. Richardson. 



Amplexopora^ Ulrich. 

 " Ramose, free or incrusting. Cellular structure as in Monoirypelldy 

 excepting that more or less numerous spiniform tubuli are developed, 

 which sometimes completely encircle the tubes. Cincinnati to sub-car- 

 boniferous." (E. O. Uh-ich, Jourti. Cincinnati Soc. Nat. Hist., Yol. Y., 

 p. 154, 1882.) 



