41 8 CRETACEOUS. 



Maiden Castle. It occurs also in outliers bet\yeen Beaminster 

 and Crewkerne. 



The Chalk of Ballard Down and Handfast, north of Swanage, is a natural 

 continuation of the Isle of Wight Chalk, the Needles of the Isle of Wight being 

 repeated in Pinnacles called ' Old Harry and his wife.' The Lower Chalk strata 

 by Ballard Hole are nearly vertical, further north a fault is met with and the beds 

 occur at a gentle angle. (See Fig. 56, p. 351.) The high inclination is continued 

 along the ridge of Purbeck Hill by Corfe Castle, where the very hard nature 

 of the Chalk may be examined. At Worbarrow Bay and Lulvvorth Cove, the 

 Chalk is also seen ; and further west it again appears on the coast at White Nore 

 and West Swyre Cliff, on the margin of Ringstead Bay, near Weymouth. Here in 

 places the Chalk is very much disturbed, the bedding being sometimes vertical 

 or even reversed.' The Chalk Marl (about twenty feet) is worked at Knowl Hill, 

 west of Corfe ; it is excavated along the dip in deep trenches. 



Along the coast near Lyme Regis and west of Seaton in Devon- 

 shire, the following general divisions have been made in the Chalk 

 (see Fig. 40, p. 252):— 



MiddL^Qialk I ^^^^^ ^^^'^ ^'"'^' ^"^ ^^^'^ nodules 100 to 150 feet. 



White (or Grey) Chalk, with sometimes hard 



brown or cream-coloured nodules 40 to 50 feet. 



Beer Stone (local). 

 Lower Chalk. -{ Chalk with quartz grains (Chalk Marl) 3 to lO feet. 



Chloritic Marl, (impersistent) nodular chalky 

 bed with green grains and phosphatic 

 nodules i to 3 feet 



These divisions are not always to be detected, for De la Beche has remarked 

 that the Chalk with quartz grains, though so conspicuous at Pinhay and 

 Dowlands, thins out near Beer, and is no longer visible at Branscombe.^ At the 

 mouth of the Axe it is about three feet thick, and contains fossils. 



W^estward of Seaton the famous Beer Stone is met with. It contains L/otrramza 

 mytiloidcs ; and consists of beds of hard sandy chalk, from 6 to 10 feet in 

 thickness, which may represent the Totternhoe Stone. Its occurrence is 

 local, but this fact is significant as showing the variable nature of the Chalk. The 

 bed has been worked, or rather mined, since Norman times ; portions of Exeter 

 Cathedral were built of it. It is much used now for building-purposes, and is also 

 burnt for lime. Similar stone was formerly dug at Ware, near Lyme Regis. 



There is no hard line of division in the Chalk series : and, as Mr. Whitaker has 

 remarked, it is often difficult to mark the junction of Chalk and Greensand. He 

 has noticed the overlap of the Upper Chalk-with-flints on to the Greensand at 

 Beer Head, and has also identified the Chalk Rock in places in Dorsetshire and 

 Devonshire. 



In Dorsetshire, Devonshire, and Somersetshire the Chloritic 

 Marl is usually very fossiliferous. It is well seen in places on the 

 coast, and also in the neighbourhood of Chard and Chardstock. 

 (See Fig. 65.) Among the specimens obtained at Chard by INIr. 

 C. Reid and myself, were Tcnhratida hipUcata, T. semiglobosa, Myo- 

 coticha cretacea, Corhnya carinifcra, Nautihis expansus, Anunonites 

 Coupei, A. navicular is, A. varians, A. Maiitelli, A. Rotliomagtnsis, 



1 Damon, Geol. Weymouth, 1884, fig. 54, p. 135, etc. 



2 T. G. S. (2), ii. 117 ; W. Whitaker, Q. J. xxvii. 97 ; W. Linford, Tr. Edin. 

 G. S. ii. iSi. 



