110 
the keels upon the last whorl, as Mons. Brongniart has 
justly observed, either smooth without any tubercle, or 
only furnished with projecting points. It may be doubted 
whether these and the R. Pes-Carbonis of Brongniart 
(Terrains du Vicentin, p. 75.), which has no angles upon 
the upper whorls, but only elongated tubercles or costa, 
are not varieties of the same species, depending upon 
locality. We find much difference among specimens 
of the recent type from different places. 
In a clay-pit at Tottenhill near Lynn in Norfolk, are 
great numbers of this fossil, as we learnt several years 
ago from Mr. Wales of Downham. We have also been 
supplied with specimens by Mr. Rose of Swaffham, who 
finds Turbo Terebra (Linn.) with them. Specimens 
have been found in Suffolk, in Crag, by the Rev. G. R. 
Leathes, of which we have represented one, but not 
perfect enough to show the three lobes of the hp. 
May it not have been such a one that Parkinson found 
in the Essex Cliff, since he describes it as having but 
one spur-like process? or did he find the London Clay 
species ? 
