214 THE CANADIAN NATURALIST. [May 



the cavities being lined with minute crystals of calc-spar : thick- 

 ness, five feet. Then come fifteen feet of light, lead-colored fissile, 

 often highly laminated limestone, which, from its hardness, forms 

 the most prominent part of the cliff, and extends in a reef down 

 to low-water mark. These beds are very rich in fossils. 



The most characteristic fossil of this bed is a Productus of the 

 true Cora type, but differing from P. Lyelli De Verneuil, in its 

 smaller size, its long perpendicular posterior marginal prolongation, 

 its more prominent and less numerous surface lines, which increase 

 by a more regular and frequent implantation or bifurcation.* 

 This Productus is exceedingly common in certain layers of the 

 shelly limestone. Among the few other forms associated with it 

 is a Bakevellia, usually indifferently preserved, and a slender 

 branching fucoid, often preserved as a carbonaceous film ; minute 

 stems of crinoids occasionally occur. It is worthy of note that 

 crinoidal remains are exceedingly rare in the limestone of the 

 carboniferous about the Basin of Minas, and I have observed only 

 the stems, which are always minute. The dip of these beds 

 varies from 35 ° to 50 ° northward ; strike, same as last observed. 



Succeeding these are beds of a very dark, blackish limestone, 

 very hard, cracking into small irregular pieces, and wearing 

 nodular: thickness five to six feet. This is full of fossils ; the 

 most characteristic is a Spirifer, which appears to differ from 

 Spirifer glabcr Martin, only in its smaller dimensions ; a small 

 Rhynconella, with large plaits (R. Ida, nob.) ; a Spirifer like 

 S. Octoplicatus, but larger. I have found here a single specimen 

 of a Phillipsia, which differs from P. Howi in wanting the 

 tubercles on the axial rings and pleurae of the side lobes, in the 

 shape of the pygidium, which is more rounded in outline, and in 

 which the grooves are distinctly marked on the six anterior 

 pleura). For this species, which appears to be new, I have 

 proposed the name of P. Vinclobonensis. Dr. Dawson has, in his 

 description of this section, in his Acadian Geology, inadvertently 

 placed this bed on the southern side of the gully about to be 

 mentioned. There is also a minute plaited Aviculopecten which 

 occasionally occurs in this bed. For this series of beds, characterized 

 by P. Cora Var. Nova-Scotica, and Spirifer Glabcr, I propose 

 the name of Avon Limestone. 



* Mr. Billings regards this as a variety of P. Cora. It may be 

 designated as Yar. Nova-Scotica, this name being proposed by Mr. Hartt. 



