Lastly, denudation, marine and subaerial, has frequently caused the absence of
deposits in one basin of corresponding age to those in the other, and this
destructive agency has been more than ordinarily effective on account of the
loose and unconsolidated nature of the sands and clays.
UPPER EOCENE OF ENGLAND.
BEMBRIDGE SERIES, A.1.
These beds are about 120 feet thick, and, as stated in Chapter 15, lie
immediately under the Hempstead beds, near Yarmouth, in the Isle of Wight, being
conformable with those Lower Miocene strata. They consist of marls, clays, and
limestones of fresh-water, brackish, and marine origin. Some of the most
abundant shells, as Cyrena semistriata var., and Paludina lenta, Figure 163
Chapter 15, are common to this and to the overlying Hempstead series; but the
majority of the species are distinct. The following are the subdivisions
described by the late Professor Forbes:
(FIGURE 165. Melania turritissima, Forbes. Bembridge.)
a. Upper marls, distinguished by the abundance of Melania turritissima, Forbes
(Figure 165).
(FIGURE 166. Fragment of carapace of Trionyx.
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