340 
LOWER OOLITIC ROCKS OF ENGLAND : 
Reference has been made (p. 254 ) to the zones adopted by 
Oppel. We cannot follow him in separating the Bradford 
Clay from the Forest Marble : broadly speaking if we take a 
Brachiopod, the zone of Waldheimia digona would best apply to 
the Forest Marble and Bradford Clay ; and if an Ammonite be 
taken, we might adopt the zone of Ammonites discus, although the 
species is' too rare to be of service in the identification of the 
strata. It is better, from a zonal point of view, to include the 
Forest Marble with the Great Oolite and Fullonian formation 
As a stratigraphical term the name Bradfordian may be 
employed generally for the Forest Marble and Bradford Clay * 
The following may be regarded as the common and charac- 
teristic fossils of the Bradfordian or Forest Marble serieaf : 
Trigonia pullus. 
Unicardium varicosum. 
Rhynchonella concinna. 
77.) 
obsoleta. 
varian?. (Fig. 67.) 
Terebratula coarctata. 
96.) 
(Fig. 
maxillata. (Fig. 78.) 
Waldheimia cardium. 
digona. (Fig. 97.) 
Terebellaria ramosissima, 
Apiocrinus Parkinsoni. 
98.) 
(Fig. 
Strophodus magnus. 
Avicula costata. 
Cyprina islipensi?. 
low can a. 
Lima c:\rdiiformis. (Fig. 75.) 
duplicata. 
Modiola furcata. 
imbricata. 
Nucula, Menkei. 
Ostrea gregaria. 
lingulata. 
Sowerbyi. (Fig. 95.) 
Pecten aunulatus. (Fig. 94.) 
-lens. (Fig 123.) 
vagans. (Fig. 122.) 
The surfaces of many of the thin bands of sandy limestone that 
occur in the upper and lower clayey divisions of the Forest 
Marble, are often traversed by remarkable tracks, evidently due 
in some cases to animals, such as Crustacea, that must have 
crossed the sandy and calcareous mud before it had time to 
solidify.J Worm-throws and burrows have also been noted. 
Ripple-marks are abundant on some of the calcareous sand- 
stones. In the limestone and also in the sandstones, there are many 
ochreous clayey inclusions or clay-galls, as they are sometimes 
called. These perhaps originate from clay-pebbles formed con- 
temporaneously by the breaking up of some argillaceous stratum. 
The shells in the limestones, both JLamellibranchs and Bra- 
chiopods, often exhibit a purplish tinge. Of the comminuted 
shells that form a large part of the limestone, Ostrea is the main 
constituent, Pecten also occurs ; showing in this as in other cases 
* The name Bradfordian was used by Lycett in 1863, Supp. to Great Oolite 
Mollusca, Palseontograph. Soc., p. 64. 
f A list of fossils from the Bradford Clay in particular, is given on p. 353. 
J Some of these tracks are like the " Zopfplatten " (Fig-tail plaits) figured and 
described in Queustedt's Jura, Tab. 46, fig. 1, and p. 334. See also G. P. Scrope, 
Proc., Geol. Soc., vol. i. p. 317 ; and Journ. Roy. Inst., vol. i. p. 538, and Plate V. ; 
Figure 1 of Scrope's Plate may be compared with that of a Crustacean track given 
by Sir J. W. Dawson, Quart. Journ. Geol. Soc., vol. xlvi. p. 598 ; see also p. 612 ; 
and Prettwich's Geology, vol ii. p. 210. 
