MIDDLE CHALK—KENT. 
379 
Zone of 
Rh. 
Cuvieri. 
Zone of 
Ter. 
gracilis. 
Glyphocyphus radiatus, Hoening. 
• =s 
o> 
R 
Hemiaster minimus, A g. - 
- 
- 
- 
R 
H 
R 
Holaster planus, Mant. 
- 
- 
R 
H 
R 
„ placenta, Ag. 
- 
- 
- 
R 
R 
Micraster corbovis, Forbes 
- 
- 
R 
II 
R 
„ Leskei, Desm. - 
- 
- 
- 
H 
R 
Ophiura sp. - - 
R 
Pentacrinus sp. - 
R 
R 
Salenia granulosa, Forbes 
- 
- 
- 
H R 
R 
Actinozoa. 
Axogaster cretacea, Londs. 
- 
- 
- 
II 
Parasmilia centralis, Mant. 
- 
- 
R 
H 
It 
Spongida. 
Camerospongia capitata, Smith 
- 
- 
* 
R 
R 
Cephalites Benettise, Mant. 
» 
- 
- 
R 
R 
„ longitudinalis, T. Smith 
- 
- 
- 
R 
R 
Cliona cretacea, Portl. 
- 
- 
- 
R 
Craticularia Fittoni, Mant. 
- 
- 
- 
R 
R 
Dory derma ramosum, Mant. 
- 
- 
- 
R 
R 
Guettardia stellata, Mich. 
- 
- 
- 
R 
11 
R 
Heterostinia obliqua, Benett 
- 
- 
R 
R 
Pachinion scriptum, JRoemer 
- 
- 
- 
R 
R 
Pharetrospongia Strahani, Sollas 
.. 
- 
- 
R 
Pholadocladia ramosa, Hinde - 
- 
- 
- 
R 
Plinthosella compacta, Hinde - 
- 
- 
- 
R 
Plocoscyphia convoluta, Smith 
r 
r 
- 
R 
R 
„ labrosa, Smith 
- 
- 
- 
R 
R 
Porosphsera globularis, Phil. 
- 
- 
- 
R 
R 
Ragadinia sulcata, Hinde 
- 
- 
- 
R 
Siphonia Koenigi, Mant. - 
- 
R 
Stelletta inclusa, Hinde 
- 
- 
- 
R 
Stichophyma tumidum, Hinde 
- 
- 
R 
Ventriculites cribosus, Phil. 
- 
. 
- 
R 
R 
„ decurrens, Smith 
- 
• 
- 
R 
R 
„ impressus, Smith 
- 
T 
- 
R 
H 
R 
,, infundibuliformis, Woodw. 
- 
- 
R 
„ mammillaris, Smith 
- 
- 
R 
H 
R 
„ radiatus, Mant. 
- 
- 
R 
R 
2. The Inland Parts of Kent. 
: The base of the Middle Chalk is well defined inland in Kent by 
the hard rough nodular beds of the Melbourn Rock. This rock, 
known at Dover as the Grit Bed, rapidly diminishes in thickness 
from 32 to only 12 or 15 feet, and in quarries it generally presents 
the characteristic features of the Melbourn Rock of Cambridgeshire 
and Hertfordshire. 
This rocky chalk is overlain bv the firm white chalk of the zone 
of Rhynchonella Cuvieri, which is divided into courses of variable 
thickness by thin seams of marl ; this gradually gives place to the 
