Vol. 56.] MR. F. W. HARMER ON THE CRAG OF ESSEX. 719 



Voluta Lamberti. 



Nassa reticosa var. costata. 



var. elongata. 



Buccinopsis Dalei. 



Buccinum undatum. 



Purpura lapilltis var. intermedia 



(the Oakley form). 

 Trophon costifer. 



(Neptunea) antiquus. 



despectus. 



contrarius. 



(Sipho) gracilis. 



Cerithium tricinctum. 

 Natica catenoides. 

 Ostrea edulis. 



Pectunculus glycimeris. 

 Pecten opercularis. 

 Cardita senilis. 

 Cardium edide var. eduliniim. 



decortication . 



Parkinsoni. 



Astarte obliquata. 



■ 2 spp. 



Cyprina islandica. 

 Tellina crassa. 

 Mactra arcuata. 



obtruncata (?). 



Pholas cylindracea. 

 Terebratula grandis. 



These are all common Waltonian species. No small forms are 

 figured by Dale, and it is strange that Purpura tetragona and 

 Artemis lentiformis, so abundant at other localities in Essex, should 

 not have been observed. On the other hand, had the Harwich Crag 

 been of the same age as that of Felixstowe in Suffolk, on the 

 opposite bank of the estuary of the Stour, forms so characteristic of 

 the latter as the existing variety of Purpura lapillus, and Tellina 

 obliqua, could hardly have escaped notice. We may therefore, 

 perhaps, include the Harwich bed in the Waltonian division, and 

 take the River Stour as the northern limit of those deposits. 



It is possible that Crag may be present beneath the Middle Glacial 

 gravel between Wrabness and Ramsey, though there is do direct 

 evidence that such is the case. I was, however, unable to trace it 

 between Little Oakley and Beaumont. South of the former locality 

 it has evidently been much denuded. 



The age of the patch of Crag at Wrabness (No. 12 in fig. 1, 

 p. 710) mapped by S. V. Wood, Jun. during his survey of Essex, 

 and mentioned by Mr. Whitaker in his Survey Memoir, 1 cannot be 

 determined, as no list of fossils from that place is in existence. 



I propose to bring before the Geological Society at an early 

 opportunity a complete list of the mollusca etc. from the Waltonian 

 Crag, together with a description of some new species. 



III. The Relation of the Waltonian Beds to other Horizons of 

 the Red Crag and to the Norwich Crag. 



While, therefore, we may group the Beaumont, Oakley, and 

 Harwich deposits with those of W^alton, notwithstanding the slight 

 differences between them, we find on crossing the estuary of the 

 Stour into Suffolk, that the fauna of the Crag-beds there exposed 

 differs from them in important particulars. 



At Eelixstowe, for example, only 3 miles north-east of Harwich, 

 a number of species, extinct or southern, which are very character- 

 istic of the Essex Crag, are more or less rare, as, for example, 



1 Mem. Geol. Surv. (1877) ' Walton-Naze & Harwich' p. 14. 



