228 
THE CRETACEOUS ROCKS OF BRITAIN, 
The accompanying diagram shows the variations in the thick¬ 
ness of the two zones in different parts of Yorkshire : — 
HI 
c3 
a 
si 
o 
AS 
ft 
£ 
m 
02 
s 
•£ 
"3 
H £ 
"d 
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^ o 
ft Q) 
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f d 
QJ 
Fh 
cS 
Sl C £ 
o'i ^ 
2 ft 
ft.S 
>> c« 
a 1 - 
7 h 
CO 
Qj 
• PH ^ 
ft 43 
a 
>> 
ftbo 
a >» 
s- 
oft 
o £ 
If 
hi £ 
a 
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o 
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qS 
c 3 
a 
a-st 
3 3 S 3 
ft ftft 
o 
W 
A 
co 
V 
r' 
< 
W 
ft 
A 
c 
Cl 
K 
H 
u 
O 
CC 
o 
a 
Co 
, 8 
w !. V 
O 
cl 1 
NOi? 
T 3 
<V 
cq 
O) 
o 
O 
« g 
X 0 > 
w C 
*> ° 
J> 4 -> 
O 02 
»—• O) 
« a 
I 
Bluish grey 
nodular chalk. 
