Alfred Bell — Age of the Suffolk Boxstones. 19 



of certain forms, but in place of Ranella gigantea, Aporrhais pes- 

 pelicani, and Yoldia ollongoides, for example, I am inclined to read 

 IVitoti flandricum, Aporrhais speciosus, and Yoldia glaherrima, all 

 well-known Oligocene or Miocene species. The Natica figured as 

 ]Sf. Alderi is not the recent form found in British seas ; it may possibly 

 be a variety of N. Nystii, like the one figured by Harder (op. cit., 

 pi. V, fig. 27). 



Another question arises in connexion with the " boxstones ", 

 i.e. how did the terrestrial mammalia and extra-local rocks become 

 associated with them, the vertebrates being of Miocene and Pliocene 

 ages, a connecting link appearing in the Mastodon tooth, described 

 by Sir E. Hay Lankester as having the valleys or hollows between 

 the cusps filled with the boxstone matrix. 



The latter writer described the detritus bed as a great beach or 

 littoral accumulation formed immediately before the Coralline Crag 

 and derived from many sources. 1 venture to suggest a different 

 solution, viz. that the older phosphatized clays were originally 

 deposited as the upper portion of the London Clay, as testified by its 

 fossils, the boxstone sands being afterwards laid down upon this, 

 both clays and sands having been but little removed from their 

 original situation. 



The sands were probably deposited in the coralline zone at 

 a moderate depth, the presence of so many double bivalves veith 

 valves closed, and the almost total absence of anj of the littoral or 

 shore-haunting molluscs, being a conspicuous feature. In due time 

 this edge of the Anglo-Belgian basin became raised above the sea- 

 level, and remained during that period of elevation as an upraised 

 plain on whose surface the animal remains referred to were 

 accumulated in local fluviatile deposits from time to time. 



Both clays and sands seem to have been desiccated and dis- 

 integrated before the time of the Coralline Crag, but not disturbed, 

 as we find it in position beneath the borders of tliis deposit at 

 Sutton and Boy ton. Beyond this it disappears, no traces of it 

 having been found by Mr. F. W. Harmer when boring into the Crag 

 outside these places. 



The detritus did not pass up into the body of the Coralline Crag, 

 but in the succeeding zones, the Oakleyan and Newbournian stages, 

 the Red Clay is full of the broken-up debris,' and flints became 

 abundant either as isolated blocks of large size and unabraded, with 

 the cortex beautifully preserved or as waterworn pieces of smaller size. 



Tinder the submarine currents of the Coralline Crag sea the floor 

 was but little disturbed, but at the close of its earliest portion, 

 the Gedgravian of Harmer, a change in the fauna commenced, and the 

 Boytonian period ushered in sundry tectonic clianges, several species 

 of northern or boreal mollusca, such as the Belas, making their 

 appearance for the first time in East Anglia. This zone or period 

 passed away, and with it a part of the older southei'n fauna, to be 

 replaced by a more northern one. The flints just mentioned were 

 due, according to Sir C. Lyell, to ice-action. Many of the smaller 



' See Bell, "Sub-Crag Detritus": Proc. Prehistoric See. East Anglia, 

 1915, vol. ii, not vol. xi as on p. 408 {ante). 



