LOWER CHALK—MICROGRAPHIC STRUCTURE. 
Hexagonal meshes, derived from Inocerami, and limonite aggre¬ 
gations, are also present. 
3. Residue of *25 to '5 mm. diameter = * 704 gr. The angular 
grains of quartz are still numerous, but in addition to these are a 
few glauconite grains, and two internal casts of Textvlaria have 
been observed. 
4. The liner residue consists of highly angular quartz, minute 
glauconite grains, and a number of limonite fragments. When 
treated with heavy liquid, sp. gr. 2*93, the limonite grains are so 
abundant as to obscure the other minerals, but on boiling with 
strong acid, they dissolve, and the remaining residue is seen to con¬ 
tain a large number of irregular red-brown and orange-yellow 
fragments of Rutile, and a number of crystals of Tourmaline of a 
blue-grey colour (having the rhombohedral terminations at one ex¬ 
tremity, but flat at the other). No fragments of zircon were observed. 
II. The Sample from Bed No. 13 of Meyer. 
Original weight, after drying = 81'59 grammes. ^ 
After solution in 20 per cent. HC1 there remained : — 
Fine insoluble residue = 2 • 30 grs. = 2 * 82 per cent., 
Heavier coarse residue=15 * 29 grs. = 18 * 74 per cent., 
therefore CaCo 3 - =78'44 per cent. 
1. Of the heavier residue 7‘46 grammes were over 1 mm. in 
diameter, and consisted almost entirely of colourless quartz grains, 
displaying every type of form, from completely rounded to highly 
angular grains. Flattened examples are also numerous. A few 
have a faint greenish-yellow mineral coating parts of the surface, 
and probably glauconitic in nature. The largest grains are 4 mm. 
in diameter. 
2. Particles from *5 to 1 mm. diameter=4* 84 grs., consisting of 
quartz and glauconite grains in about equal proportions. 
(a) The quartz grains are similar to those described above. 
(b) The glauconite is mostly in the form of well-preserved casts, 
the chambers being still united together, and thus it marks 
the internal outlines of the foraminifera in which it was 
enclosed. Beautiful crozier-sliaped forms, recalling species 
of Haplophragmium, are fairly common, but the most 
numerous types are those recalling species of Bulimmci, 
especially B. variabilis, and B. pupoides. Species of 
Cristellaria having the pyramidal terminal chambers such 
as are found in G. gibba were also frequently observed. 
(c) The delicate silicified tests of Foraminifera are also numerous, 
mostly with single chambers, but in one case a perfect 
specimen of Gaudryina pupoides , showing the primary 
triserial arrangement, and subsequent biserial succession is 
beautifully preserved. 
T 
