COASTS VISITED BY THE ARCTIC EXPEDITION. 601 



the aperture is not seen, neither is the columella, or the outer lip, com- 

 plete, so that I have to base my determination upon the body-whorl. 



The fascia, or band, is a quarter of an inch wide, having gently 

 curved concave lines of growth or deposit, i. e. concave or thrown 

 backwards with relation to the lip ; the upper and lower areas of the 

 body-whorl (above and below the fascia) are marked by delicate 

 lines of growth in reverse position, and lying at an angle of 30°, 

 that above the fascia being to the right, that below to the left ; the 

 shell must have been 5 or 6 inches in length. Billings, in the 

 " Geology of Canada " (Gcol. Survey of Canada, vol. i. Paheozoic 

 Fossils, p. 234), figures from the Chazy series a shell he calls M. 

 Augusiina, which quite equals in size the above species, but wants 

 the broad fascia. 



Log. Oflley Island, 81° 16'. .Dr. Coppinger's collection. 



Muechisonia, ? sp. (PI. XXV1T. fig. 2.) 



"Whether this is a Macrocheilus or a Murchisonia I am at a loss to 

 know : the shell measures 4§- inches in length, and must have had 

 seven or eight whorls ; four interior moulds of the lower whorls are 

 left to us, but no outer shell remains to aid in the determination or 

 description of the species. Many large Canadian and North-Ame- 

 rican forms have been described and figured by Billings and Hall 

 &c. from rocks about the same horizon ; it is not, however, safe to 

 refer our single specimen to them : it does not possess any fascia or 

 band round the whorls, a character peculiar to Murchisonia ; but we 

 have no true shell remaining. 



Loc. Oflley Island, lat. 81° 16'. In white limestone, collected by 

 Dr. Coppinger. 



Genus Bhaphtstoma, Hall, 1847. 



Bhaphistoma iEQUALE (?), Salter. 



Baphistoma cequdle (?), Salter, Murchison's Siluria, ed. 4, p. 197, 

 foss. 40. f. 2. 



Helicites qualteriatus, Schloth. 



Platyschisma, Euorrvphalus, Scalites, Bhaphistoma, Helicotoma, and 

 flattened forms of Pleurotomaria so resemble each other when crushed 

 or in the form of casts, that it is no easy matter to distinguish them, 

 all appearing much the same when masked by the matrix in which 

 they occur. Although we have only one specimen from Cape 

 Hilgard, there can be no doubt about the genus. B. cequale, Salter 

 (Helicites Gualteriatus, Schi.), seems to be our shell. It is asso- 

 ciated with Maclurea magna, Halysites catenulatus, Favosites goth- 

 landicus, and Favistella. I refer it to B. cequale, which it more 

 nearly resembles than any American form I am able to find. The 

 upper surface of some of the acuminate forms of Maclurea, which 

 have the margin of the whorl extremely acute, would pass for this 

 shell ; but the last whorl when exposed is not so deep as in Maclurea, 

 it is flatter and more acute and discoid also. Again, the subtrigonal 



