4t> C GEOLOGICAL SURVEY OP CANADA. 



irregular, but mostly annular, siliceous concretions, and the 

 concave face looks as if it had been broken from a much 

 thicker mass. When viewed with a lens the coral is seen to be 

 made up of minute, polygonal, thin-walled, contiguous and con- 

 tinuous corallites, of different sizes, apparently arranged in 

 groups. The larger corallites are about one-sixth of a line in 

 diameter, and the smaller from one-eighth to one-tenth of a 

 line. The cells are entirely filled with mineral matter, and 

 the sha]3e and position of the tabula? cannot be satisfactorily 

 defined. 



Zaphrentis, Nov. sp. Two imperfect specimens of an apparently 

 undescribed species of Zaphrentis or Sirepielasma. 



Actinoceras Lyoni, Stokes. The types of A. Lyoni are from Igloolik 

 and Ooglit, in Arctic America, but Dr. Bigsby, on page 170 of 

 the " Thesaurus Siluricus," gives Fort Garry as one of the locali- 

 ties of this species. A. Mchardsoni of Stokes, from Lake Winni- 

 peg, may be the same shell in a different state of preservation, 

 for, according to Stokes' descriptions, the only difference between 

 A. Lyoni and A. Mchardsoni is that in the former " a small tube 

 is seen within the siphuncle, but no radii have been traced from 

 it," while in the latter the tube is said to be small and " sur- 

 rounded by numerous lamina? or plates filling up the siphuncle." 

 In Stokes' figures, however, the siphuncle of A. Lyoni is repre- 

 sented as larger in proportion to the size of the shell than it is 

 in A. Mchardsoni. In the extremely large size of their siphuncle 

 and in the apparently entire absence of any radii proceeding 

 from the central tube, which latter cannot be discerned at all in 

 some individuals, the two specimens collected by Dr. Bell at this 

 locality, and several others from Stone Fort, Manitoba, in the 

 collection of the Survey, agree much better with the descriptions 

 and figures of A. Lyoni than with those of A. JRichardsoni. 



Ilkenus, Sp. (allied to and possibly identical with I. latidorsatus, Hall). 

 An imperfect cast of a small llkenus, most likely the same as the 

 trilobite from Fort Garry referred by D. D. Owen to I. crassi- 

 cauda, Wahlenberg. The specimen collected by Dr. Bell is, 

 however, clearly not the true I. crassicauda, for in the original 

 figure of that species in the "Petrificata Telluris Suecana?" 

 (pi. 2, figs. 5 and 6) the central lobe of each of the ten body rings 

 is represented as equal to about one-third of the entire diameter, 

 whereas in the specimen from St. Andrews the central lobes of 

 the body segments are equal to nearly three-fourths of their 



