LOWER CHALK—SOMERSET AND DEVON. 119 
part of the section was noticed in a previous volume, and to the 
description there given we now add particulars of the Chalk. 
The upper part—which is being continually cut back to obtain 
chalk for lime-making—showed in 1892 about 15 feet; it is a nearly 
white, very pure chalk, with a few flinty siliceous nodules. About 
4 feet above the Greensand it passes into a somewhat lumpy or 
nodular glauconitic chalk, of which there is about 18 inches. This 
passes down into sandy glauconitic chalk full of quartz grains (about 
2 feet), and below this is a hard nodular sandy and glauconitic rock, 
from 9 to 12 inches thick, full of brown phosphatic lumps, and 
containing many fossils. 
This phosphate conglomerate rests directly on the hard calcareous 
sandstone which forms the summit of the Selbornian stage. 
There is a complete passage from this basement-bed up into the 
white chalk. The quartz grains, which are large and abundant 
in the basal limestone, rapidly lessen in number upwards, and dis¬ 
appear in about 3 feet. The matrix of the basement-bed is a chalky 
limestone ; the brown nodules in it are of various sizes, some small 
and like phosphatic nodules elsewhere, others large, and these when 
broken are seen to be only lumps of very hard quartziferous lime¬ 
stone, coated and partly infiltrated with phosphatic matter. These 
seem to be lumps of a somewhat older bed, broken up and 
phosphatised, and then embedded in the present nodule-bed. 
The fossils also are of two kinds: some are merely brown 
phosphatic casts, much waterworn, and often covered with small 
Serpulse and Polyzoa. These clearly belong to the same category 
as the small phosphatic nodules. The majority of the fossils, how¬ 
ever, including all the larger Ammonites, are well preserved, even the 
Ammonites retaining the shell, though this often comec away in 
extracting them from the rock. 
This fossiliferous rock has generally been called Chloritic Marl or 
Chloritic Chalk, but we do not regard it as the equivalent of the 
Chloritic Marl of Wiltshire and the Isle of Wight, but rather as a 
condensed representative of the lower part of the Chalk Marl 
An account of the beds above described was written by Mr. J. 
Wiest, and published in Davidson's “ Monograph of the Brachio- 
poda " (Pal. Soc., 1852), Vol. I, p. 114. The succession is correctly 
given, and six different beds are distinguished, but three of these 
really belong to the Upper Greensand, and only the three higher 
to the Chalk. The basal limestone of the latter is Mr. Wiest’s 
No. III., which he called “ the Scaphites bed," and described as “ a 
compact accumulation of fossils." The overlying glauconitic chalk 
(No. 2) he calls the “ Chalk Marl or Discoidean stratum," and he 
specially mentions Ammonites Mantelli , Discoidea cylindrica, and 
Ananchytes subglobosus among its fossils. In this he is quite correct, 
but an inverse order would indicate their relative abundance, Eolas¬ 
ter subglobosus being particularly common in this glauconitic chalk, 
and much less so in the “ Scapkites bed " below. 
