S. V. Wood, Jan. — Sequence of the Glacial Beds. 67 



myriads, in association with almost as great a profusion of Tcllina 

 calcarea and Tcllina pretrnuis, the three forms being always distinct. 

 In the Lower Glacial, though Tcllina prelenuis becomes somewhat 

 rare, and has not yet occurred higher in the scries, the other two, 

 Tcllina ohliqua and Tcllina calcarea, occur in abundance in that 

 formation, and also maintain themselves together in the Middle 

 Glacial, and even into the Upper ; while Tcllina calcarea, an existing 

 Arctic shell, alone occurs in the Scotch beds. Tellina ohliqua, having 

 long preceded Tellina calcarea in existence, for it occurs in the 

 Coralline Crag, thus preceded it in extinction. 



Conversely, Mija Uclclavallensis, one of the most conspicuous types 

 of the beds of the Clyde basin, occurring also in the Caithness 

 Boulder clay, and not known living nearer than Canada, is unknown 

 to all the English Glacial series older than e ; but it is mentioned by 

 Mr. Leckenby^ as having been found by him in the chalkless purple 

 clay of Scarborough cliffs, which Mr. Rome and T refer to the similar 

 chalkless clay, e, which caps the clays with chalk in the Holderness 

 cliffs. 



These circumstances seem to indicate that while such of the 

 Scotch beds as yield this Mya approximate in time nearer to the 

 newest of the English Glacial series (the clay e) than to any other, 

 none of the beds of this part of Britain, except the one in Aberdeen- 

 shire, (and such extensions of it as may prove to exist,) and perhaps 

 one at Kilmaurs in Ayrshire, described by Dr. Bryce,^ belong to 

 any older part of the series than the Upper Glacial, e' e' and e. 



The close analysis which the subject requires will I trust excuse 

 the length to which this paper has extended. 



Note. — Since the foregoing paper was written, I have, with the 

 assistance of Mr. Harmer, largely augmented the list of mollusca 

 from the East Anglian Middle Glacial. The number, exclusive of 

 several that cannot be reliably identified by reason of the obscurity 

 of the fragments, is now 56. The specimens have been studied 

 and compared with great care by my father ; and one of the shells, 

 a Mangelia, appears to be quite new, while another differs sufficiently 

 from Mangelia linearis as, perhaps, to necessitate its separation. 

 With the exception of these two, and of Tellina Balthica, the whole 

 are Coralline, Red, or Fluvio-marine crag forms ; and include 

 Tellina ohliqua, Nucula Cohholdice, Nassa granulata ; N. retiiosa var 

 costata Purpura incrassata, Turritella incrassafa (this in profusion), 

 Cardita scalaris, and other extinct forms. The fauna presents gTeat 

 dissimilarity from that of the Lower Glacial pebbly sands, on the one 

 hand, and from that of Bridlington, on the other ; while it possesses 

 no affinity with any of the following, viz., Blackpool, Moel Tryfaen, 

 Macclesfield, Severn Gravel, Kelsea-hill, Glacial beds of East of 

 Scotland, or the Clj^de beds. On the other hand, all the peculiarly 

 Crag shells, enumerated by Mr. Jamieson from the Aberdeenshire 

 "Crag gravel" of 1860, except Valuta Lamherti (and that even I 

 have reason to believe has occurred in it), are among this 56. The 

 fauna is clearly not derivative, and it has a preponderatingly 

 1 Geo. Mag., Vol. II., p. 347. ^ Quar. Jour. Geol. Sec. toI. xxi., p. 216. 



