376 Mr. R. Taylor on the Alluvial Strata 



chalk with numerous layers of flinty forming insulated cliffs of chalk*. 

 Several circumstances lead me to consider these masses as the remnant of a 

 stratum which existed further to the north-east in the space now occupied by 

 the sea, constituting- a higher part of the series than the chalk of Norwich. 

 Some violent convulsion has evidently deranged the position of the chalk at 

 these places. The layers of flint are about four feet asunder, and they un- 

 dulate in a very remarkable manner. These masses are continuous with a 

 solid bed of chalk discernible at low-water, reaching nearly a mile in length, 

 from Trimingham to Sidestrand, and forming a level platform extending into 

 the sea. Along this platform we see well displayed the parallel strata of flint, 

 and the larger and least destructible of the fossil remains, such as the belem- 

 nites and echinites. The chalk of this platform is harder than that of Cromer 

 or Norwich. The sea has now nearly washed away that part of the chalk- 

 cliff* which formerly abounded with that remarkable fossil shell presented by 

 me to Mr, Sowerby, and by him figured under the name of Magas pumilus. 

 That which particularly distinguishes this stratum is the vast abundance of a 

 small curved oyster, called Ostrea canaliculata. Almost every part of the 

 chalk is crowded with these shells, and many of the flints have from twenty to 

 fifty of them adhering, which in that case, being hardened by the siiex, afford 

 the best specimens. The flints abound also with sponges and branching 

 alcyonites, so numerous that scarcely one flint is found without some traces 

 of them. In this stratum are found two species of Echinus ; viz. a large 

 Galea, and a Conulus from three quarters to one inch and a half in diameter ; 

 also spines of echini ; a large obtuse, and a small fusiform belemnite ; four spe- 

 cies of Terebratula ; pectines ; Modiola parallela ; dentalia; serpulie ; madre- 

 pores and fragments of pentacrinites, almost all of which fossils are pecuhar 

 to this stratum, and differ essentially from those of the chalk at Norwich. 



A few miles to the north and west of this spot at Trunch and Cromer, de- 

 tached portions of this chalk are worked for lime. At Cromer a large portion 

 of chalk has been washed away by the encroachments of the sea ; the point 

 called by mariners Foulness being evidently the site of a former extension 

 of the chalk-strata. The memorials of the former existence of this mass of 

 chalk are heaps of ponderous chalk flints, which now form dangerous shoals 

 for shipping. The fossils adhering to these flints resemble those of the chalk 

 at Norwich. 



The chalk in the neighbourhood of Norwich is characterized by its 

 softness and whiteness ; by its strata of flints, and by its fossils. It is best 



* These insulated masses of chalk are noticed in Mr. Greenough's Geological Map of England. 



