490 
THE CRETACEOUS ROCKS OF BRITAIN. 
Where these beds come down to level of high-water-mark, they 
seem to have been crushed, and present a different aspect, which 
has been described by Mr. Fox-Strangways, from whose memoir the 
accompanying sketch is taken. * He states that the under surface 
of the Middle Chalk (bed d) is sharply defined, and is scored with 
slickensides. 
Fig. 84.—Junction of Lower and Middle Chalk in Bnckton Cliff. 
f. g. Chalk with flints in regular 
beds. 
e. Thin bed of chalk with flints. 
d. Very hard chalk, crushed and 
striated on the under sur¬ 
face ; full of chalcedony. 
c. Band of dark coaly shale. 
b. Chalk much crushed, with 
veins of chalcedony. 
a. Chalk without flints, irregu¬ 
larly bedded. 
Fossils are not abundant in the Middle Chalk of Yorkshire, with 
the exception of Inocerami, which are common throughout, and the 
list of recorded species is rather longer than that for Lincolnshire. 
The following are all the occurrences that I can be sure of in the 
several zones :— 
Zone of 
Eh. 
Cuvieri. 
Zone of 
Ter. 
gracilis. 
Ptychodus mammillaris, Ag. 
Inoceramus Brongniarti, Sow. 
„ Cuvieri, Sow . - 
,, mytiloides, Sow. 
t ,, undulatus, Mant . 
Ostrea vesicularis, Lam. 
t Spondylus fimbriatus, Goldf 
Rhynchonella Cuvieri, d'Orb. - 
Terebratula semiglobosa, Sou). - 
Terebratulina gracilis, var. lata, Eih. 
Bourgueticrinus ellipticus. Miller 
Galerites subrotundus, Mant. - 
Holaster planus, Mant. 
t Salenia granulosa, Forbes 
x 
x 
x 
X 
X 
X 
? 
X 
X 
X 
X 
V 
X 
X 
X 
X 
* Geology of the Country around Driffield, Mem. Geol. Surv., 1886, p. 10. 
t Inserted on. the authority of the Bev. J. F. Blake. 
