M2 
THE CRETACEOUS ROCKS OF BRITAIN, 
CHAPTER III. 
THE LOWER CHALK OF THE KENTISH COAST. 
General Description. 
We propose to commence our detailed stratigraphical account 
of the Lower Chalk with the section exposed in the cliffs between 
Folkestone and Dover, because this section is easily accessible; it 
has been already described by several writers, and the fossils have 
been collected from its several portions (zones and subzones.) 
The earliest description is that by William Phillips in 1818 (Trans. 
Geol. Soc., Vol. v. Pt. 1, p. 16), who recognising the difference in 
colour between the upper and lower portions of what we now know 
as Lower Chalk, called the lower part “ Grey Chalk,” and classed 
the upper as part of his “ Chalk without flints." To the upper 
he assigns a thickness of about 50 feet, and correctly describes it 
as having few organic remains, and states that it is separated from 
the hard massive chalk above by a band of soft marl. The thickness 
of the Grey Chalk he estimates at “ not less than 200 feet/' which is 
more than its real thickness, but he does not seem to have recog¬ 
nised the existence of the “ Greensand ” between it and the Gault, 
and consequently he does not fix its base. He remarks that where 
the Grey Chalk first rises from the beach, “ its separation from the 
Chalk without flints is not at that place perfectly defined ; in less 
than a quarter of a mile beyond this place the two strata are very 
distinct; the white being separated from the grey by some very 
thin beds of a sandy appearance and yellowish colour.” 
We have referred to Phillips’s account more particularly because 
it remained the only description of the section for more than half a 
century, and was referred to by Mr. Whitaker in 1872 as “ one of 
the best local descriptions (of the Chalk) that has been pub¬ 
lished.” * Mr. Whitaker supplements this description by a 
few notes of his own, remarking that the soft bed at the 
top is about 6 feet thick, and contains Belemnites, and 
that the 50 feet of chalk beneath is “ thickly bedded, breaking 
into large blocks.” Of the Grey Chalk he says, “ the top seemed 
to me fairly marked near Shakespeare’s Cliff by the change 
of colour, the grey chalk having wavy dark lines along the bedding. 
Near the top there is a more massive bed, about 8 feet thick, which 
at Hay Cliff has small hard projections, some being pyrites, some 
fossils, and others stony lumps.” He also comments on the “ great 
* Geology of the London Basin, Mem. Geol. Survey, Vol. iv. p. 30, 
