and its Organic Remains.. 85 



among some of the most abundant genera : Pectunculus, Cy- 

 prma, Cytfierea, Astarte, Venericardia, Osirea, and Pecten. 

 In most instances these shells can be distinguished from those 

 of the red crag by a difference in their appearance, not de- 

 pending upon any peculiarity in the shells themselves, but 

 owing to the circumstance of their not having been subjected 

 to attrition, and to the soil in which they are imbedded con- 

 taining a smaller proportion of the oxide or hydrate of iron. 



We might reasonably conclude that a deposit presenting 

 the appearances just described, would be more favourable for 

 the preservation of the organic remains peculiar to the crag 

 aera, than those parts of the formation which had previously 

 been explored, and we accordingly find that not only are the 

 shells generally in a more perfect condition, but that numerous 

 species abounding here have not been discovered in the su- 

 perincumbent strata. A far more important circumstance is 

 that many of the most common and characteristic shells of 

 the red crag have not been obtained from the coralline; in 

 illustration of which may be mentioned the total absence of 

 Buccina and Murices, two genera which, perhaps, of all others 

 are distributed in the greatest profusion throughout the whole 

 of the upper beds. 



I cannot, however, proceed further, without alluding to the 

 very valuable information connected with the organic remains 

 of this stratum which I have received from Searles Wood, 

 Esq. (of Hasketon near Woodbridge), who by the most active 

 and persevering exertions has more than trebled the amount 

 of Testacea usually assigned to the crag; and his cabinet 

 exhibits so extensive a series of these fossils, as will probably 

 for a long period far exceed that of any other collector. 

 Having communicated to Mr. Wood my intention of draw- 

 ing up the present observations, he very kindly furnished me 

 with an account of his collection. The following is an extract 

 from a letter dated March 1835. 



" With respect to the two distinct formations in Suffolk, 

 you will be able to point out how far you think they extend. 

 I have never observed the lower bed to the westward of the 

 river Deben : the locality you speak of at Tattingstone, I must 

 have overlooked. That there are two distinct beds in Suffolk, 

 is an observation that has long been made ; I have heard my 

 friend the Rev. G. R. Leathes speak of a distinct stratum of 

 shells and corals at Ramsholt, nearly twenty years ago, and 

 he then remarked how much they resembled those of the crag. 

 In the lower bed are found a few teeth of cartilaginous fish, 

 and some vertebrae of the spinous species. The more charac- 

 teristic shells of the crag 1 have not yet observed, but from 



