18 SUPPLEMENT TO THE CRAG MOLLUSCA. 



Buccinum undatum, LinnS. Crag Moll, vol. i, p. 35, Tab. Ill, fig. 12. Supplement, 



Tab. II. 



Localities. Red Crag, Sutton. Upper Glacial, Bridlington? Post-glacial, Kelseahill 

 gravel {Jeffreys), and Nar brick-earth {Rose). 



Localities of var. tenerum. — Red Crag passim. Fluvio-marine Crag, Bramerton and 

 Thorpe ; Chillesford bed, Bramerton and Horstead. Middle Glacial, Billockby and 

 Hop ton. Post-glacial, The March gravel. 



In the 'Crag Mollusca' I have figured three different forms under the specific name 

 of undatum, and I have here introduced three more. 



Eig. 2, Tab. II, Supplement, appears to resemble what has been called B. 

 Groznlandicmn. Fig. 3 of the same plate is an extreme variety as to its ornamentation, 

 which I will call Buc. undatum, var. clathratum. Buc. tenerum of c Min. Conch.,' t. 486, 

 figs. 3, 4, which the late Dr. S. P. Woodward in his list of Norwich Crag shells refers to 

 cyaneum ? may possibly be distinct. Fragments of tenerum (principally of the columella) 

 occur in the Middle Glacial sands of Billockby and Hopton Cliff, while perfect specimens 

 of it exactly resembling those of the Red Crag and of all ages abound in the Post-glacial 

 Fen gravel of March. The constant features maintained by tenerum in the Crag, when 

 found to recur in so modern a formation as the Fen gravel, impress me with the belief 

 that this is a distinct species. Buc. undatum ('Crag Moll.,' Tab. Ill, fig. 12, c) is very 

 rare in the Crag, while the form tenerum swarms in it. In the numerous specimens 

 sent to me from March by Mr. Harmer I have not seen the true form of B. undatum, 

 and as this Post-glacial gravel of March presents a more Arctic character than the 

 present British seas I am disposed to believe B. tenerum may be B. cyaneum. 



Supplement, Tab. II, fig. 5, represents a specimen from the Red Crag of Butley which 

 has much perplexed me. There is an angularity in the upper part of the volution, below 

 which it is contracted. The upper part of the volution is slightly striated, and there are 

 some striae on the base or lower part of the body-whorl, with very faint indications of 

 undulations upon the spire, like those of undatum, with reflected imbrications upon the 

 columella. The spire is much depressed, but it looks like a distortion, and I have 

 considered it as such for the present. I will call it B. undatum, var. ovulum. The axis 

 of the shell is ^ths of an inch. 



Purpuha lapillus, Linne. Crag. Moll., vol. i, p. 36, Tab. IV, fig. 6. 



Localities. Red Crag passim. Fluvio-marine- Crag, Bramerton and Thorpe. Lower 

 Glacial, Belaugh, Rackheath, and Weybourne. Middle Glacial, Billockby and Hopton. 

 Post-glacial, Kelsey Hill and March. 



The variety crispata occurs in the Chillesford bed at most of its localities and in the 

 Lower and Middle Glacial sands. In the Middle Glacial the form incrassata is in 



