458 Fossils of the Chazij Limestone. 



MURCHISONIA PERANGULATA? (Hall.) 



Murchisonia perangulata (Hall), Palceont. N. Y. Vol. 1, page 41. 



Plate 10, Fig. 4. 



Several specimens have been collected which closely resemble 

 those found in the Black River Limestone, but are a little larger 

 than the average size. 



Locality and Formation. — Mingan Islands. Chazy Limestone. 



Collectors — Sir W. E. Logan, J. Richardson. 



Murchisonia asper, N. s. 



Description. — Obtusely conical ; apical angle about 70° ; spire 

 of four or five whorls, — the body whorl large, ventricose, with a 

 prominent band about the middle, and a low angular carina at 

 about two-thirds the distance between it and the suture above. 

 The upper whorls small, rapidly tapering to an acute apex, and 

 altogether forming only one-fourth or less of the whole length. 

 The band on the body whorl of a specimen a little more than 

 one inch and a half long is two lines wide, and consists of a cen- 

 tral rounded ridge one line wide, with an obscurely angular 

 carina on each side. The surface is ornamented with fine sharp 

 lines of growth from six to eight in the width of one line, which, 

 in descending, curve gently backward until they reach the band ; 

 below which they curve abruptly forward for about two lines, 

 then become vertical or nearly so, and again curve backward on 

 approaching the aperture. They are thin, sharp, imbricated, and 

 very distinct. The aperture, as exhibited in a single specimen, 

 is nearly circular, the lower part somewhat effuse, the inner lip 

 entire and a little separated from the body whorl. 



A full-sized individual is twenty lines in length, of which, on the 

 anterior side, the aperture and body whorl occupy full fifteen 

 line, and the remainder of the spire to the apex only five lines ; 

 but on the opposite side, the spire, from the body whorl upwards, 

 is seven lines. The width, measured across at one line above the 

 upper angle of the aperture, is eleven lines. The shell in this 

 specimen, at the lower side of the body whorl, is one line and a 

 half thick. 



In some of the fragments of other specimens there appears to 

 be a wide, but very shallow, concave band just below the princi- 

 pal band on the body whorl, and below this an obscure carina. 

 The main band also varies a little in its proportional width and 



