UPPER AND LOWEE CHALK OF DOVER, ETC. 233 



been described by Mr. F. G. H. Price, F.G.S., in his paper " On 

 the Beds between the Gault and Upper Chalk at Folkestone"*. He 

 divides the chalk into nine beds. Bed 6, with its characteristic 

 fossil, Holaster suhglohosus, represents the division which in the 

 geology of Cambridge is called the Lower Chalk. Bed 7 is called 

 the zone of Belemnitella i^lena^ and Mr. Price describes it as a 

 yellowish gritty chalk, forming a marked contrast to the beds above 

 and below. I have no doubt that this bed of yellowish chalk 

 represents the zone of Belemnitella plena as recognized by Mr. 

 Jukes-Browne and myself in Cambridgeshire, Hertfordshire, &c. 

 As in these counties, it is marked by thin bands of laminated marl, 

 and it contains the same fossils — Belemyiitella plena, Ostrea vesicularis, 

 and Rhynchonella plicatilis being the commonest forms. 



Above this zone, the Middle Chalk begins. An excellent section of 

 the lower portion of it may be seen by ascending the cliff-path at the 

 western entrance of the tunnel of the South-Eastern Railway through 

 Shakespeare's Cliff (fig. 1). It will be found here that the yellowish 

 gritty chalk is overlain by exceedingly hard, rocky, nodular chalk, 

 the first 32 feet of which constitutes the "■ Grit Bed " of Mr. Price. 

 The peculiar nodular character of the chalk does not end here, but 

 extends upward for some distance, the chalk becoming gradually 

 softer, and the nodules arranged in layers, the last marked one being 

 about 70 feet above the base of the " Grit Bed." 



Above this the chalk is dull white, rather soft, and contains irre- 

 gular indefinite lines of flints, the first flint line being about 60 feet 

 above the nodular chalk. 



The height of the clift" here is perhaps 150 feet above the base of 

 the " Grit Bed,'' so that about two thirds of the Middle Chalk is 

 shown ; and although the whole of it is seen in Shakespeare's Cliff, 

 there is no accessible place where the highest horizons can be 

 examined. The strata dip gently to the east ; and it will be found 

 that the chalk exposed above the beach at the eastern end of the 

 town of Dover is but little, if at all, above the horizon of that seen 

 at the top of the cliff at the western entrance of Shakespeare's-Cliff 

 tunnel. Here, as before, the chalk is rather soft, dull white in 

 colour, with few flints. Several well-marked marl-bands may be 

 seen in the lower portion of the cliff. Above the uppermost of these 

 the chalk becomes streaked or veined with grey and harder portions, 

 weathering into knobby lumps or projections. These lumps are of 

 hard crystalline chalk, and frequently show the structure of sponges 

 or ventriculites in iron-stains. From the first they show arrange- 

 ment in layers, and gradually becoming closer and denser the chalk 

 passes into a bed of rock composed of these hard lumps or nodules 

 set in a softer matrix. Above this, similar rocky beds, at irregular 

 distances from each other, alternating with layers of softer chalk, 

 continue for about 25 feet ; these, becoming less defined, pass gra- 

 dually into softer chalk, which still contains hard crystalline lumps. 

 There then occurs a compact yellowish rock, about 10 feet thick, 

 which, in its turn, gradually passes into softer chalk, with layers of 

 * Quart. Journ. Geol. Soc. vol. xxxiii. p. 431. 



