62 REPORT—1857. 
in chemical changes had not before been noticed. It concluded by expressing a doubt 
if electricity and heat could be the same agent, or modification of it, as equivalents 
of substances always produce, in combining, the same amount of electricity, but very 
different amounts of heat. 
GEOLOGY. 
Notice of the occurrence of a Boulder of Granite in the White Chalk of the 
South-east of England. By Rosert Gopwin-Austey, P.R.S. 
Tue author described first the threefold division of the cretaceous series of the 
South-east of England; the extent of the area occupied by each division, and the 
conditions of accumulation thus severally implied—that, commencing from shallow 
water, each shows more extended boundary lines, and increasing depth. 
1. Littoral shingle of Lower greensand or Neocomian group at Farringdon ; deepest 
deposits in Neocomian clays, with Bivalves in normal position, not exceeding ten 
fathoms. 
2. Gault had its deep beds over South-east parts of England, its littoral ones in the 
West, as in the Halden-sands. 
3. The area of the white chalk ranged as far North as the North of Ireland, and 
from the coast of Scotland to the area of the Baltic, and thence occupied a broad 
zone over North Germany. In Western Europe the conditions under which the white 
chalk was accumulated were remarkably uniform; for the whole of the Anglo-French 
basin (Seine), 800 feet may be taken as its average thickness, the whole a deep-water 
accumulation. : 
Rolled shingle and fragments of extraneous rocks have been found in the chalk, 
and are to be seen in several collections; they are all of crystalline, mostly granitic 
rocks, and their size is not considerable; yet in every case they are beyond the moving 
power indicated by the white chalk, 
Modes of transfer of marginal materials into great depths are,— 
1, By floating sea-weeds. Illustrations of this are to be seen on most coasts, and 
evidences of it may be detected in most of the older sedimentary deposits, 
2. By floating ice. 
Description of the Croydon Granite Boulder,—Form, size, and weight such that it 
could only have been moved by ice; other materials associated with it, such as rounded 
pebbles of other crystalline rocks and siliceous sand. Such an association of materials 
sinking in one place, shows that they were held together in the act of sinking, as also 
when they sank into the fine calcareous mud of the chalk sea-bed. 
The author abstained from entering upon a description of the rocks found associated 
with the Croydon boulder, but stated that such an assemblage existed only in the 
Scandinavian and other northern regions. 
The inferences to be derived from the foregoing considerations have a very inter- 
esting bearing on the physical geography of the North European area, at the period of 
the greatest expansion of the Cretaceous sea. There were regions of the globe then, 
as now, where coast-ice was periodically formed, was broken up and dispersed ; these 
regions lay to the north of the area of the white chalk of West Europe, and the white 
chalk ocean extended continuously up to such latitudes. : 
Why, if ice was the transporting agent, such materials are not more common, was 
explained with reference to the present course taken by the icebergs and ice-floes of 
the Atlantic. 
During the Drift period of the Pliocene division of geological history, the set of the 
liberated ice was more eastward, and was dependent on considerations which are well 
understood and can be made available for every geological period. 3 
On Carboniferous Limestone Fossils from the County of Limerick, collected — 
by the Geological Survey. By W. H. Batry, .GS. 
The author in this communication gave a brief notice of an extensive collection of — 
fossils recently made by the Geological Survey in the neighbourhood of Askeaton 
