440 
THE CRETACEOUS ROCKS OF BRITAIN. 
The gritty chalk at the base contains glauconite grains, and passes 
down into the rough glauconitic sand with chalky matrix, which 
here forms a kind of passage bed between the Turonian and Ceno¬ 
manian stages. It will be noticed that in the short distance be¬ 
tween the Pinnacles and this cliff all the beds have thickened, 
and the total is 26 in place of 21 feet; also that the hard upper 
iimestone of the Pinnacle and Beer Head sections is not here dis¬ 
tinguishable, but its place is doubtless at the top of Mr. Meyer’s 
No. 16. 
Fig. 33 is reproduced from a photograph of the cliff where the 
above section was taken, and Mr. Meyer’s numbers are marked on 
the beds in the middle of the cliff. 
A little west of the talus slope, and in a re-entrant angle of the 
cliff, is an adit (visible in Fig. 33), whence Beer Stone was formerly 
extracted. Dressed blocks of the stone still lie about on the slope 
below, alongside the pathway leading down to the shore, where the 
stone was shipped, but since the making of the railway to Seaton 
this quarry has not been worked. 
The Beer Stone is a bed of very local occurrence, hardly trace¬ 
able as a freestone in Beer cliffs, as we have seen, but probably 
extending from the great quarries west of Beer in a southerly direc¬ 
tion to this part of the cliffs. 
From this point the zone we have been following rises high into 
the cliffs, and can be followed with the eye for some 200 to 300 
yards; then it partakes in the rapid and remarkable thinning out 
of the Cenomanian, and is finally overlapped by the chalk of the 
Terebratulina zone (see Fig. 80). Nor, so far as can be seen does it 
come in again in any part of the cliff east of Branscombe Mouth. 
It is not easy to ascertain exactly what happens in the Hooken 
cliffs, where certain beds thin out and disappear, because they are 
practically inaccessible ; but so far as I could ascertain by scanning 
the lines in the cliff from below the disposition of the beds appeared 
to be as represented in Fig. 74. If my view of it is correct the pheno¬ 
menon must be regarded as partly a case of contemporaneous erosion 
and partly one of thinning out of beds against a bank. I assume 
that originally the beds A and B were continued westward over 
the Selbornian, though possibly becoming somewhat thicker in 
that direction, and forming a kind of sand bank ; then the sea ffoor 
seems to have been swept by a current which removed the material 
of B and nearly the whole of A from a portion of the area. It is 
difficult to understand how this tract continued to form a sub¬ 
marine bank, and yet, if we suppose that the zone of Rhynchonella 
Gumeri was also continuous over the tract in question, we must 
assume another period of erosion after its formation, and the struc¬ 
ture in the cliffs does not suggest any such second erosion. The 
beds, especially those of the Terebratulina zone, seem to come 
down and thin out against the Bed A as if against a submarine 
bank. 
