1914-15.] Chalk Boulders from Aberdeen, etc. 
267 
Insoluble in Acid. 
Rock. 
*o 
<1 
c3 
o 
c5 
o5 
Composition of Coarse Residue. 
o 
2 
S3 
'o 
02 
Per cent 
m 
’o 
o 
*m 
o 
03 
.s 
*cc 
o 
03 
o 
O 
Minerals. 
Max. Size | 
of Grains. i 
Average Size 
of Grains. 
Organisms and 
Other Ingredients. 
B 9 
Fragment of a 
large boulder of 
greyish - white 
chalk. Ice- 
scratched. 
91-32 
8-68 
5-27 
Quartz, mica, 
chlorite, felspar. 
-17 
•09 
Residue largely 
aggregations of 
siliceous matter. 
Sponge spicules, 
Radiolaiia, silice- 
ous casts of Fora- 
minifera. 
B3 
A flattish ellip- 
tical boulder, 
chalk white 
with grey veins. 
87-68 
12-32 
7-22 
Quartz, mica, 
chlorite, felspar. 
-18 
•09 
More than half the 
coarse residue con- 
sisted of aggrega- 
tions of siliceous 
matter. Sponge 
spicules, arenace- 
ous Foraminifera, 
and siliceous casts. 
Radiolaria. 
B5 
A small rounded 
pebble of softish 
white chalk. 
95-74 
4-25 
3-97 
-28 
Quartz, felspar, 
mica, chlorite. 
(A few spherules 
of pyrites. ) 
Chiefly Tetracti- 
nellid spicules of 
snow-white colour. 
A few Radiolaria. 
Fragments of sili- 
cified vegetable 
matter. Siliceous 
casts of Fora- 
minifera. 
B 11 
Fragment of a 
boulder of hard 
white chalk. 
Ice-scratched. 
96-72 
3-28 
3-05 
-23 
Quartz, mica, 
felspar, chlorite. 
-22 
•10 
Tetractinellid 
spicules, Hexact- 
inellid mesh, 
globate forms 
numerous. A few 
Radiolaria. Silice- 
ous casts of Fora- 
minifera. 
A4 
A flattened 
boulder of hard 
greyish - white 
chalk. Ice- 
scratched. 
97-07 
2-93 
1 
2-72 
-21 
Quartz, felspar, 
muscovite, zir- 
con. 
-58 
•14 
Sponge spicules 
chiefly Tetracti- 
nellid forms, some 
Hexactinellid 
mesh. Several 
species of Radio- 
laria. Fragment 
of silicified vege- 
table matter. 
A1 
Small rectangu- 
lar boulder of 
hard white 
chalk. 
97-45 
2-55 
2-49 
-06 
Quartz, felspar, 
muscovite, bio- 
tite, chlorite, 
tourmaline, leu- 
cosene. (Pyrites 
and a few grains 
of glauconite.) 
-27 
•12 
A few fragments of 
spicules and one 
well-preserved Ra- 
diolarian. Silici- 
fied vegetable frag- 
ments. 
