XIX. — On the Alluvial Strata and on the Chalk of Norfolk and Suffolk, and 

 on the Fossils hy which they are accompanied. 



By R. TAYLOR, Esq. of Norwich. 



[Read May 2, 1823.] 



1 . On the Alluvial Strata, above the Chalk. 

 In the present account of the alluvial strata and of the chalk I shall begin 

 with the highest beds, proceeding from east to west. 



Alluvial beds occupy the principal part of the surface of Norfolk and Suf- 

 folk. The extensive alluvial clays of those counties contain numerous water- 

 worn fossils, which are exposed in excavations, or are found dispersed over 

 the surface of the arable lands. In the retentive clays of High-Suffolk, these 

 fossils consist of large belemnites, to which serpulae are often found adhering, 

 of the Gryphaea dilatata, Ostrea deltoidea, &c., and occasionally of the frag- 

 ments of large ammonites and vertebrae. Mixed with these fossils are septaria 

 and nodules of pyrites. 



On the sides of the valleys which intersect these clay districts, we find beds 

 of alluvial gravel, in which is a profusion of waterworn belemnites, either 

 detached or inclosed in nodules of indurated clay. At Eye in Suffolk belem- 

 nites are mixed with elephants' teeth and other organic remains. Roydon 

 gravel-pit, near Diss, on the northern bank of the Waveney river, abounds 

 with belemnites, ammonites, echini and their spines, serpulae, cardia, myae, 

 tellinae, modiolae, ostreae, pectines, plagiostomae, terebratula), inocerami, 

 fragments of pentacriniles, and of bones. We there find Ostrea gregarea, 

 Astarte planata, Venus turgida, Unio Listeri, &c. 



Along an intermediate line between the high clay-lands and the outcrop of 

 the chalk-strata, we find at Bury St. Edmunds, Weston, Hopton, Harling, 

 Dunham, Wereham and Swaffham, in pits of clay and marl above the chalk, 

 large blocks or boulders of a gray or greenish sandstone, distinguished by its 

 peculiar fossils. These fossils are small, pointed belemnites; Terebratula 

 ovoides, T. plicata and T. gigantea ; casts of small ammonites ; Avicula me- 

 dia; and species of the genera Trochus, Unio, Astarte, Venus, Tellina, Car- 

 dium, Isocardia, and Pecten. In the same pits with these boulders are found 

 detached belemnites, similar to those of the high clay-lands, five species of 



