14 LOWER OOLITIC ROCKS OF ENGLAND : 
Clay. Some layers in the Lincolnshire Limestone, especially 
those near the clay-coverinsr, are stained various shades of red. 
The Forest Marble is very generally of a bluish colour as the 
stone-beds are interstratified with clays. 
Stratigraphictd characters of Oolitic rocks, 
The stratigraphical evidence shows that the rocks now under 
consideration, which are mainly composed of oolitic grains, are all 
more or less false-bedded, and sometimes minutely current-bedded : 
hence the grains must have been formed before they were drifted 
and accumulated in their present positions. 
Comminuted shells occur in some of the oolitic limestones, and 
we find gradations from beds composed of oolitic grains to those 
mainly formed of shell-fragments. 
The tranquilly-deposited strata, that are associated with these 
false -bedded oolites, are white more or less earthy limestones and 
marls, that contain in places scattered oolitic grains or clusters of 
them ; they also yield occasional quartz grains. 
Of such beds we have instances in the Oolite Marl of the 
Inferior Oolite of the Cotteswolds, in the Lincolnshire Limestone 
near Lincoln, in the Fuller's Earth Rock, and in the White 
Limestones of the Great Oolite. 
Sandy sediments containing oolitic grains are also met with, in 
the Great Oolite and Corallian Series. 
In some of these beds we have evidence of Coral -growths. 
They occur not in situ in the false-bedded freestones, but in the 
earthy limestones and marls that are developed at different 
horizons in the series of more or less oolitic limestones : in the 
Oolite Marl of the Inferior Oolite, in the white limestones of the 
Great Oolite, in the Coral Eag above the Coralline Oolite. 
It may be said that the occurrence of masses of oolitic freestone 
is thus associated with Coral-growths, and that the formation of 
the granules is more or less dependent on nuclei, and on the 
disturbed condition of the waters in which they were formed. 
That oolite granules are formed under other conditions, is well 
known ; and further reference will be made to this matter. In 
the case also of the oolitic ironstone of the Middle Lias, there is 
no particular evidence of current-bedding to point to a disturbed 
condition of the waters. 
Pisolite. 
Of the little concretions known as Pisolite, the best known 
examples occur in the " Pea Grit " at the base of the Inferior 
Oolite of the Cotteswold Hills. There are however equally 
important layers in the Corallian Beds near Sturminster Newton 
and elsewhere. More particular reference to these will be given 
in the chapters that refer to the several formations. 
It should however be mentioned that Mr. E. Wethered in 
1889* announced the discovery in the Pisolites, both of the 
* Geol. Mag., 1889, p. 196. 
