604 



S. S. BTJCKMAN ON AMMONITES FROM 



Localities. This species marks a distinct zone, which is just on the 

 top of the sands or passage-beds. This zone is about a foot thick at 

 Bradford Abbas, but about 3-4 feet at Corton and Hawthorn Downs. 

 Harpoceras Murchisonce occurs at Bradford Abbas, Marston Road, 

 Corton and Hawthorn Downs, and other places, and also rather 

 plentifully, but badly preserved, at Haselbury. 



There is a variety (?) which I am inclined to think should be 

 separated from Harp. Murchisonce. It has a smallish umbilicus and 

 very fine ribs, and is far thinner. I have given it the name of 

 Harpoceras MurcJiisonos, var. bradfordiense, S. S. B. 



Dimensions of a medium-sized specimen of Harp. Murchisonce : — 

 Diameter 2*85 inches, umbilicus 0*96, breadth of aperture 0*70 ; 

 outer whorl, back to front, 1*20 inch. 



Haepoceeas ctcloides (d'Orb.). 



1845. Ammonites cycloides. d'Orb. Pal. Franc. Terr. Jurass. pi. 121. 

 figs. 1-6. 



1856. A. cycloides (d'Orb.), Oppel, Juraformation, p. 370. 

 1867. A. cycloides (d'Orb.), Waagen, Geogn. Pal. Beitriige, p. (92) 

 598. 



Localities. Humphriesianum zone at Oborne and quarries near 

 Sherborne, somewhat plentiful; also at Wyke Quarry, but scarce. 



A variable species, some specimens being very thick, with a small 

 umbilicus and coarse ribs, and others thin, with larger umbilicus and 

 smaller ribs. The two varieties, however, merge one into the other. 



D'Orbigny has well represented the two extreme forms. 



This species was formerly quoted by the name of Amm. Cado- 

 ■ mensis, on account of the misprint underneath d'Orbigny's plate. 



Haepoceeas Levesquei (d'Orb.) ? 



Ammonites Levesquei, d'Orb. Terr. Jurass. pi. 60 (misprinted 

 Solaris, Phillips). 



I quote this species with some hesitation, as our specimens seem 

 to have fewer whorls and somewhat more marked ribs. 



Our specimens are from the zone of Harpoceras Sowerbyi at Brad- 

 ford Abbas, Halfway House, &c. ; not very common. 



Haepoceeas Edouaedianum (d'Orb.) ? 



1845. Ammonites Edouardianus, d'Orb. Terr. Jurass, pi. 130. figs. 

 3-5. 



1856. A. Edouardianus (d'Orb.), Oppel, Juraformation, p. 370. 



1881. A. Edouardianus (d'Orb.), J. Buckman, Quart. Journ. Geol. 

 Soc. vol. xxxvii. p. 61 , no. 3. 



Our specimens do not seem to agree very well with d'Orbigny's 

 figures, and are perhaps not the same. Thej T have a more open 

 umbilicus and far less inclusion ; consequently the whorls are less 

 across. 



Locality. Humphriesianum zone at Oborne : scarce. 



