A. 8f B. Bell — On the English Crags. 261 



The Upper Crag to consist of the uppermost beds of Eed Crag, 

 the Chillesford Scrobicularian Crag, and the Fluvio-marine, and 

 marine Crags of the Norwich Series. The uppermost beds of the 

 Eed Crag overlying the lower at Shottisham Creek, Eamsholt Dock, 

 and possibly at Bawdsey and other parts south of Butley Corner.^ 



Putting aside the question of physical structure as not bearing 

 upon our argument, we may yet observe^ that in most instances com- 

 minuted fragments are more abundant in the Lower Eed Crag than 

 in the Upper. 



The reason why Mr. Prestwich could not observe any order of 

 succession in the greater part of the Eed Crag, we believe to be, that 

 there is not any order, physically speaking, but only palaeonto- 

 logically. The oblique lamination of Mr. Prestwich, and the beach 

 stages of Mr. Wood, junior, constitute, in our view of the question, 

 one distinct stage, and not more. In a valuable map appended to 

 Mr. Wood's paper on the Eed Crag, a hori2iontal stage overlying 

 certain beach stages is shown, but for want of systematically work- 

 ing out the fauna of his sections, he has only foreshadowed the great 

 truth (as we think) embodied in them as shown by their organic 

 contents, that his horizontal Crag, as a whole, possesses a fauna so 

 vastly different from that of his beach Crags, that their agreement, 

 in point of community of species, is hardly more than their dis- 

 agreement. 



This observation, of course, only applies to the district we have 

 worked. In the coming summer we hope to trace this Upper Crag 

 south of the Deben ; Mr. Wood has done so physically, we hope to 

 do so paleeontologically.^ 



It seems as yet to have escaped the notice of most observers, that 

 the fauna of the Eed Crag presents two aspects, i.e. a deep-water and 

 a shallow- water one ; and herein lies the solution of a difficulty met 

 with in comparing different pits. As judged by the fossils, the 

 lower Crag sea was deepest about the localities of Waldringfield and 

 Sutton, evidenced by the presence of Terebratulce in large numbers, 

 especially at the former section, and which shallowed out towards 

 Walton-on-the-Naze. In the upper deposit the deepest water oc- 

 curred at Shottisham Creek, becoming shallower towards Butley, 

 Chillesford, Tunstall, and farther to the north. At Shottisham Creek 

 we have obtained several specimens of Bhynchonella psittacea, to- 

 gether with many Terebratulae, the latter measuring from J inch to 

 If incheS' or more in length ; Fusus Largilliertii and F. Turtoni also 

 being found in the same place. 



It is a characteristic of modem sea life that the deep-water fauna 

 is more persistent in time than the shallow-water one, and it is so in 



1 In justice to ourselves we ought to say that our investigations in the horizontal 

 Crag were hegun long before our attention was called to Mr. Wood's map, or paper. 

 Should the physical and palseontologieal evidence concur, as we believe it will, the 

 question as to the superposition of the Upper Crag over the Lower will be settled, 

 and it will then be necessary to show the agreement in the fauna of all the deposits 

 which we have comprised under the heading Upper Crag. This must, however, be 

 left till a future opportunity. A slight indication how matters stand in this direction 

 is all that we now propose giving. 



