234 
LIAS OF ENGLAND AND WALES: 
f Irregular beds of micaceous and ferruginous sandy 
| rock, full of casts of shells. These form two or 
three beds of stone, in places more or less calcareous. 
They do not, however, present the characteristic 
features of the Rock-bed, but are always of a 
more or less nodular character. They contain 
Belemnites, usually grouped together in con- 
siderable numbers in certain parts of the rock, 
Middle Lias. -^ and also a few rounded pebbles or concretions like 
those of the Rock-bed. The species of fossils 
found in these bands were as follows : 
Pecten lunularis (large, 5 inches in diameter). 
Avicula novemcostae. 
Cardium truncatum. 
Leda complanata. 
Light-coloured clays containing bands of ironstone- 
( nodules (of considerable thickness). 
| The lowest beds seen at this point are exposed in the 
brickyard below, and consist of blue, micaceous 
clay, containing flattened nodules of clay-ironstone 
Jwith a few fossils : 
Belemnites (fragments). 
Ammonites capncornus. 
Leda complanata. 
Cardium truncatum. 
Ostrea. 
Wood. 
On the south side of Slawston Hill the Marlstone is scarcely 
traceable. The Middle Lias here may be from 60 to 70 feet in 
thickness. At the north-west end of Slawston outlier, the Rock- 
bed of the Marlstone presents its usual characters, and consists of a 
hard calcareous rock containing Avicula noi-emcostce, Rhynchonella 
tetrahedra, and Terebratula punctata. Large nmsses of car- 
bonate of lime, crystallized in the forms known as " Dog-tooth 
spar " and " Nail-head Spar," are seen in the rock at this place. 
Below the Marlstone there were exposed in the railway-cutting, 
about 50 feet of blue shales with bands of ferruginous rock, and 
in the upper portion of the shales Ammonites margaritatus has 
been found.* 
Near the bridle-road leading from Keythorpe to HaDaton, and 
at the point where it crosses the brook, some old pits exhibited the 
following section, described by Prof. Judd: 
Uooer Lias / Laminated shales with traces of the "fish 
\ and insect beds " at the top - - 5 to 6 feet, 
f Rock-bed with usual characters, containing 
numerous Belemnites, Ammonites annu- 
latus, Terebratula punctata, &c. As is 
| often the case with this rock, it here 
Middle Lias. -^ contains numerous rounded pebbles or 
concretions - - - 1 ft. seen. 
Light-blue clays passing down into clays 
with bands and nodules of ferruginous 
and micaceous rock. 
The irregular mode of recurrence of the diminutive repre- 
sentative of the Marlstone Rock-bed, is illustrated in the following 
sketch of a section seen at this point (Fig. 69). 
* J. Marriott, Rep. Leicester Lit. and Pliil. Soc. for 1883-84, p. 80. 
