480 
THE CRETACEOUS ROCKS OF BRITAIN. 
with a throw of about 10 feet runs through this pit, and the beds 
measured on the east side of it in. 1879 were : — 
feet. 
Terebra- 
tulina 
Zone. 
Soil and chalk rabble ------ 
Hard white chalk with a layer of flint nodales, which 
{ are grey inside ------ 
i White chalk with vertical joints and a thin seam of 
1 marl at the base ------- 
Zone of 
Rhyne k. 
Cuvieri. 
Hard greyish chalk in beds about a foot thick with 
marly partings - 
Loose grey marl with small nodules of hard chalk - 
l Greyish white chalk in two beds - 
Lower f Loose grey marl, enclosing hard yellowish nodules 
Chalk. I Hard 
grey 
chalk 
3 
13 
oi 
8 
oi 
o 
4-j 
1 
6 
Its thickness here, therefore, is only between 10 and 11 feet, 
and is about the same in a quarry south-east of Calcebv. 
In the large quarry at South Thoresby the zone is a little 
thicker; here the beds dip to the south-west and the Middle 
Chalk is thus brought into the western face of the pit, along 
which the following measurements were taken in 1879 : — 
feet. 
Middle , 
Chalk, ) 
Lower 
Chalk. 
6 . White chalk with flints - - - - - 
5. Layer of white chalk about 6 inches, broken by 
frequent vertical joints (Columnar Bed) - 
4. Layer of grey rubbly shale - - - - 
3. Hard buff coloured chalk, very shelly and con 
taining Inoceramus mytiloides, in beds from 
12 to 18 inches thick 
2 . Variegated marl, red, grey, green, and buff 
1 . Hard pinkish white chalk (see p. 220) 
5 
0 | 
12 
i* 
n. 
A similar section is seen in a chalk-pit near Swaby, of which 
Fig. 82 is a sketch, the numbers referring to the beds above 
mentioned. 
Near Louth this zone is exposed in several large quarries, both 
on the south and on the north side of the town. It varies from 12 
