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hexagonal forms and sections. These grains are accompanied 
by smaller comminuted grains of the same quartz, which fill up 
the interstices, the whole being feebly cemented together with 
diffused Carbonate of Lime, &c. Occasionally a few specks of 
iron pyrites occur. The carbonates effervesce with the mineral 
acids.” 
This description corresponds to the analysis made of the 
rock in the Chemical Laboratory of the College here, the result 
being as follows :— 
Sand (silica present as insoluble silicates) 60°74 
Lime (Calcium carbonate)... ss s. 34°35 
Iron (Ferric oxide) ... tc a9 Be 
Manganese and Alumina ... ae aad 64 
Chloride of Sodium ... =p Bc a2 
Magnesia (as Carbonate) ... j 
It will be seen that the term Calcareous Sandstone, which I 
have employed is the correct designation of this stone. The 
rock varies both in colour and in specific gravity in certain 
defined areas, to be hereafter noticed. 
The fact that this stratum is highly fossiliferous and that 
its fossils are in excellent preservation contributes to the 
interest it has excited. We have made at the College three 
separate collections of these fossils, and Mr Bravenper has 
made an extensive one as well. The Ammonitidae are very 
abundant and of all ages, some reaching enormous dimensions. 
One I measured was 1-ft. 10-in. in greatest diameter. The 
Lamellibranchie and Brachiopoda are in some cases exceptionally 
fine. I have one block which consists entirely of Brachiopods 
in such preservation that in some which are broken open the 
shelly arm-supports are seen encrusted with minute crystals of 
calcite, the rest of the interior being still hollow, or only 
partially filled in. Our collection contains, already identified :-— 
CEPHALOPODA 
Cosmoceras calloviense Cosmoceras cordatus 
" modiolaris (sub-leevis) Nautilus hexagonus 
” Chamousetti Belemnites hastatus 
y Kenigi u Oweni 
” Gowerianus 
