Vol. 51.] MURCHISONIA AND ITS ALLIES. 221 



the whorl than in the type of M. dxspar. The surface of the 

 Belgian specimen, however, is not well preserved, and the ornamen- 

 tation ahove, being finer than that below, would be more easily 

 obliterated, and many of the British specimens show no traces of it, 

 or merely one or two of the stronger lines. Moreover there is some 

 variation in the height of the angle above the suture ; therefore I 

 am inclined to consider the Belgian shell a variety of this species. 

 M. dispar differs from the shell referred (but with a query) to 

 H. angidata, Phill., 1 in possessing a greater spiral angle, whorls 

 more convex in outline, and more obliquely set, less strong keels, 

 and also in having lines above the band. It may, however, prove 

 to be a variety of that form, of which most of the specimens that I 

 have seen are merely portions of the upper part of the spire. A 

 fragment of a specimen of M. dispar (PI. VIII. fig. 8) in the col- 

 lection of Mr. J. Wright comes very near that described as M. an- 

 gulata, the keels below the band being stronger than usual, and 

 the surface of the upper part of the whorl not quite so convex. 

 But it is difficult to form a just comparison, as the shell is deformed 

 by pressure. Phillips, in ' Pal. Poss.' p. 150, gives Northumberland 

 as a locality for M. angulata, so he may possibly refer to this shell. 



E. Tietze considers a Devonian shell identical with this species ;; 

 he gives no description, and his figure is very small. 



In the Woodwardian Museum there are three specimens from 

 Lowick, all small and merely casts, only one of which, the type, 

 shows traces of ornamentation. It is embedded in the matrix, and 

 portions of five whorls are exposed whose length is 13 millim. 

 (PI. VIII. figs. 5, 5 a). There are two larger specimens from the 

 same locality, one in the Museum of Practical Geology, London, and 

 the other in the Newcastle-on-Tyne Museum. The former is as 

 cast, and the latter is but little better ; both have the angle rather 

 higher up the whorl than the type. 



Formation. Yoredales (d 3 ). 



Other individuals are from the Avon Section, Clifton, ten of which 

 are in the Bristol Museum, three in the British Museum (Natural 

 History), and three in Owens College Museum, Manchester. These- 

 agree with the type in having the angle situated low down on the 

 whorl. The largest is in the Bristol Museum : five whorls are 

 preserved, and there are traces of two others ; the apex is broken. 

 If entire, the shell would probably consist of about ten whorls. 

 Length of five whorls=43 millim. ; width = 19 millim. (PI. VIII. 

 fig. 4.) 



In the Woodwardian Museum there are also two casts of this 

 species from Settle. The largest has six whorls preserved, whose 

 length is 53 millim. ; width of body-whorl = 22 millim. 



Four shells from Cork appear to be identical with this species ; 

 one is in the Museum, Queen's College, Cork, and the other three 

 are in the collection of Mr. J. Wright, Belfast. They are all more 

 or less compressed obliquely, but the surface is well preserved. 



1 ' Notes upon some Carb. Species of Murchisonia in our Public Museums,' 

 Quart. Journ. Geol. Soc. vol. xliii. (1887) p. 621, pi. xxiv. figs. 1, 2. 

 Q.J. G. S. No. 202. k 



