262 



J. E. Marr — Glacial Deposits. 



exhibit its full growth, so that it is impossible to say whether an 

 angular carina sets in on the last whorl or not. Judging by its. 

 general agreement with our other specimen, I am inclined to think it 

 would, and in that case the chief difference between this shell and 

 Alaria semicostulata disappears. Again, in the Chipping Warden 

 specimen (Fig. 16) the whorls are more rotund and more deeply 

 sutured than in the enlarged figure of A. semicostulata, given by 

 Piette, or in the first above-described specimen. Slight variations 

 in the convexity of the whorls, in the depth of the sutures, spiral 

 angle, and arrangement of the spiral lines, are not by themselves 

 characters of specific value amongst otherwise similar Alarice ; so 

 that in face of the general agreement of these shells with A. semi- 

 costulata, and failing definite proof of any important distinction in 

 the keel, the carinal spines, or the canal, I consider it safest to 

 relegate both of the above specimens to that type. 



[For the Plate and the Explanation thereof, see the May Number, p. 202.] 



IV. — The Glacial Deposits of Sudbuky, Suffolk. 



By J. E. Marb, M.A., F.G.S., 

 Fellow of St. John's College, Cambridge. 



THE accumulations of drift in the vicinity of the town of Sudbury 

 have been described by Mr. Whitaker in the Geological Survey 

 Memoir upon the N.W. part of Essex and N.E. part of Herts, etc. ; 

 and additional notes are given by the same author in the Memoir upon 

 the Geology of Ipswich, etc. Since the appearance of these memoirs 

 the sections have altered considerably, and one of the exposures is 

 of such interest, that a record of it seems to me desirable, as in a 

 few years it will be doubtless destroyed, and one more link in the 

 chain of facts which have to be considered in attempting to account 

 for the mode of formation of these drifts will have disappeared. 



I wish to express my indebtedness to Dr. J. S. Holden, F.G.S., 

 who has kindly accompanied me to the principal exposures, and 

 furnished me with much information. 



Fig. 1.— Section in Mr. Green's Pit N.E. of Sudbury. 

 Length of Section about 100 feet. 



N. 



A. Chalk. 1. Boulder-clay. D. Gravel dug over and filled in. 



J5. Thanet Sands. 2. Gravel and sand. T. Talus. 



C. Bed Crag. 3. Loam. 



C Bed Crag caught up in drift. 



The section to which I would call special attention is seen in 

 Mr. Green's pit, about a quarter of a mile N.E. of Sudbury Town Hall. 

 The accompanying Figure (Fig. 1) shows its appearance at the 



