C“ 5» 
372 THE CRETACEOUS ROCKS OF BRITAIN. 
with interspersed flints is separated from that with few flints by 
bed of marl 2 or 3 inches thick ” ] further, that about 20 feet 
glow that bed two somewhat thicker beds of soft chalk marl run 
parallel with each other, and with the line of separation, and at 
about 3 feet apart.” Lastly, beneath the topmost thin bed of marl 
“ two thin beds of separate flints are very visible.” The accuracy 
of this will be seen by comparing it with the vertical section given 
in the later paper referred to. * 
In 1874 Hebert published a detailed description of the Middle 
and Upper Chalk as seen near Hover.f This we shall have occasion 
to discuss further on, and need only here mention that he gives a 
table comparing his divisions with those of Phillips, and that his 
divisions are as follows : — « 
Metres. 
Craie KTIplaster planus - - - - - - 8 or 127 
Inoceramus lahiatus , divided into 
a. zone superieur a Rhynchonella Cuvieri et Inocer¬ 
amus Brongniarti - - - - 35 f 
b. zone moyenne, craie noduleuse a Am. nodosoides 
and Am. rusticus ----- 25 
c. zone inferieure, craie argileuse a Bel. plenus - 14 
Professor Barrois in 1876 adopted Hebert’s divisions, but made 
a somewhat different grouping, referring the zone of Bel. plenus (c) 
to the Cenomanian or Lower Chalk, calling the next division ( b ) 
the zone of Inoceramus labiatus, and (a) the zone of Terebratulina 
gracilis. These two zones, with that of Holaster planus , he grouped 
as Turonian. 
In 1877 the lower part of the Middle Chalk as seen near Lydden 
Spout was described by Mr. F. G. H. Price, || who employed the 
old classification of Lower Chalk without flints and Upper Chalk 
with flints, so that his measurements ceased at the first line of 
flints. His Bed viii., which he calls the “ grit-bed ” or zone of Car- 
diaster pygmceus, is the lower 32 feet of Barrois’ zone of Inoc. 
labiatus and his Bed ix. includes the rest of this zone and part of 
the zone of Terebratulina gracilis , with a thickness of 118 feet up 
to the first line of flints, which Mr. Price took as the base of the 
Upper Chalk. 
In 1880 the Middle Chalk, as developed in Cambridgeshire, was 
defined and established, H and in 1886 Mr.W. Hill studied the Middle 
Chalk of Dover and compared its sub-divisions with those estab¬ 
lished in Cambridgeshire.** In 1897 Mr. Hill re-examined the 
* On the Beds between the Upper and Lower Chalk of Dover, by 
W. Hill, Quart. Journ. Geol. Soc., Vol. xlii. p. 232 (1886). 
+ Comparaison de la Craie des cdtes d‘Angleterre avec celle de France, 
Bull. Soc. Geol. de France, Ser. 3, T. ii. p. 416. 
7 These thicknesses are much too little. Hebert appears to have thought 
that the chalk at the base of the cliff east of Dover belonged to the top of 
the nodular chalk d Am. nodosoides^ and so missed out about 70 feet. 
II Quart. Journ. Geol. Soc., Vol. xxxiii. p. 431. 
IT “On the Sub-division of the Chalk,” by A. J. Jukes-Brcwne. Geol. 
Mag., Dec. II., Vol.vii., p. 248. ' ~ - 
**Villiam Hill, Quart, Journ. Geol. Soc., Vol. xlii. p. 232. 
