434 
THE CRETACEOUS ROCKS OF BRITAIN. 
slice of rock has recently moved outwards without slipping far out 
of position. The difficulty of reaching this position prevented me 
from examining it; Dr. Rowe, however, measured it in 1898, and 
informs me that the Rh. Guvieri zone has a thickness of 56 feet. 
The same beds can be examined on the opposite side of the Whit- 
lands valley at the south-west end of Lynch Plantation, 30 or 40 
feet being seen, and consisting partly of loose and partly of massive 
chalk in alternating beds with many Inoceramus mytiloides ; as 
before there is a glauconitic and quartziferous basement bed. 
A fourth place where there is a clear and fairly accessible section 
of the Rh. Guvieri chalk is below the Coast Guard station on Whit 
lands cliff. Here there seem to be 50 or 60 feet assignable to this 
zone, and the basement beds are well exposed in a sort of alcove at 
the bottom of the vertical cliff. The section here is as follows: — 
ft. in. 
Rough chalk, full of small chalk nodules ---60 
Hard nodular quartziferous chalk, with Rhyne. Wiesti, 
Inoc. mytiloides and Discoidea Dixoni - 19 
Greenish sandy and glauconitic chalk, with some 
scattered phosphate nodules; Actinocamax plenus 
and Am. ( Douvilleiceras) euomphalus - - - 0 9 
Hard shelly limestone, with a layer of brown phosphatic 
nodules at the top -------10 
Selbornian. Hard calcareous sandstone. 
Though the fossils found in the lowest 9 inches of sandy glau¬ 
conitic chalk link this rather with the Lower than with the Middle 
Chalk, it passes up into the hard quartziferous chalk. 
At the corner of Charton cliff, a little further west, the base is again 
exposed, and the section, though small, is remarkable, for there is 
no Cenomanian limestone, and the quartziferous chalk rests 
directly on the topmost bed of the Tipper Greensand. 
Lower down, and a little to the eastward, a more complete section 
was found in a large fallen mass. This showed : — 
feet. 
Firm shelly chalk, with hard yellow nodules standing out on 
the rough weathered face - ----- 10 
Hard rocky nodular quartziferous chalk, with a marked 
yellow layer at the top . ..2 
Plane of separation with flattish lenticular lumps of phos¬ 
phatic matter and a few nodules. 
Selbornian. Hard calcareous shelly sandstone - - 6 
In the quartziferous and glauconitic chalk here I found Ino¬ 
ceramus mytiloides , Gar diaster pygmoeus, Discoidea minima , and 
Gidaris hirudo , all Turonian species. Here, therefore, the Lower 
Chalk is absent, and the Middle Chalk has a glauconitic basement-bed. 
Passing to Rousdon cliff, the lower part of the Middle Chalk is 
exposed in the bank by the roadway just above the old quarry, 
and the basal beds are exposed at the top of this quarry. By the 
roadway a specimen of Am. [Acanthi] rusticus was seen. Prom this 
point westward the chalk of the Rh. Guvieri zone can be followed 
continuously in the cliffs for about a mile, hut is not always 
accessible, except in the fallen masses. 
