GEOLOGICAL SECTION. 19 
waters. The conversion of wood into Coal was considered, as also 
were the climate, and the nature of the atmosphere of the Coal 
period. Attention was drawn to the distribution of Coal in England, 
and to the probable duration of these supplies. . It was shewn that 
the question “ How long will our Coal last?” is one of national 
importance, as our great industries have become concentrated upon 
Coal fields, and were this Coal to be exhausted, would pine away. 
In 20 years time the pinch will be felt in the Welsh Coal Fields, 
as all the thicker and more productive seams are being rapidly 
worked out. Possibly the developement of the Coal Measures 
which have recently been discovered in the East of England will 
do something towards resuscitating the industries which at one 
time flourished in that quarter. 
In conclusion, Mr. Hichens gave an account of his own 
experiences in Coal Mines, and explained with some detail the 
necessity for good ventilation, and the means by which it is 
obtained, and the cause and prevention of explosions. The 
principle and use of Davy’s Safety Lamp were demonstrated by 
chemical experiments, and throughout the Lecture the various 
points were illustrated with the aid of the Oxy-Hydrogen Lantern. 
Meeting held Nov. 6th, for private business—The President 
proposed the following rule which was carried :—‘‘ That each 
member of the section must come to two meetings out of every 
three, or he shall cease to be a member of the Section.” 
Mr. Hichens then delivered an address on “Sedimentary 
Rocks.” He began by explaining the different bases of classifi- 
cation of Rocks which are possible, Rocks might be arranged 
according to their chemical composition, or hardness or colour—as 
3 matter of fact they are, by the way in which they were produced. 
Sedimentary Rocks are those due to the accumulation of sediment. 
The origin of a Sedimentary Rock such as sandstone was traced, 
details being given as to the carrying power of water, and the 
formation of deltas. During the Challenger Expedition it was 
proved that all sediment, no matter bow fine it may be, reaches the 
scean bed within a distance of 300 miles from the land. Attention 
«as drawn to the milkiness of a glacier stream, due to the fine 
spatter carried in suspension : when the current stops the matter 
ac 
naturally sinks to the bottom. 
‘The loose sediment is turned into a solid rock by pressure, as 
layer accumulates upon layer, and partly by a process of infiltration 
