LOWER CHALK—LINCOLNSHIRE. 
228 
In a quarry half a mile south-east of Calceby it consists of dull 
red laminated marl (18 inches), with 6 inches of rubbly marl below 
containing lumps of hard yellowish chalk. 
At South Thoresby it has again a different aspect, being well 
exposed there in the western part of the quarry N.E. of the village ; 
here it consists of variegated marl and chalk in three layers, each 
about 6 inches thick ; the upper is a yellowish laminated marl; 
the middle consists of grey lumpy and marly chalk, the lowest 
of soft mottled marl, red, buff, and green. 
Half a mile W.N.W, of Swaby it is 3 feet thick, and consists of 
pink shaly chalk above, passing down into mottled grey and purple 
marl, which has a basement layer of loose lumps of hard chalk. 
This rests on an undulating surface of the hard pink chalk below. 
In Mr. Larder’s quarry by the London Eoad, just south of Louth, 
the zone is represented by 18 inches of soft argillaceous marl, of a 
bluish-grey, variegated with red, and enclosing hard chalk pebbles 
at the base. On the north side of Louth, at Mr. Paddison’s quarry, 
there are two beds of grey marl with a course of marly chalk between 
them (see p. 221). 
To the westward near the main escarpment, and one mile E.S.E. 
of (layton-le-Wold, a small pit exposes the following section:— 
ft. 
Chaiky soil and broken marly chalk 2|- 
Buff-coloured marl, with a band of chocolate-red marl in the 
middle and a layer of hard yellowish chalk pebbles at the 
base - - - - - - - - - - - ll 
Hard yellowish-white chalk, with thin seams of red and yellow 
marl - -- -- -- -- - 5 
In North Lincolnshire this horizon is exposed in two quarries 
near Caistor. One of these, three-quarters of a mile east of Nettle- 
ton Church, shows the following beds : — 
ft. 
Middle (Hard buff-coloured chalk, with shaly seams - 5 
Chalk. (Softer marly chalk - - - - - - - 2| 
(Soft laminated marl, light grey at top and bottom, with 
Lower a purplish band in the middle {Belemnite Marl) - 1} 
Chalk. Hard cream-white chalk in regular beds 5 
Talus concealing lower beds.20 
The other quarry is three furlongs south-east of Caistor, and 
the variegated marl is exposed at the bottom. 
The section in the large quarry at South Ferriby has been given 
above, and here the zone of Act. plenus exhibits a more normal 
character, consisting of two marly bands with a course of 
grey marly chalk between them. Here, too, Act. plenus is not an 
uncommon fossil, whereas in the rest of Lincolnshire it is so rare 
that no specimen was found during the progress of the Survey. 
