34 
POPULAR SCIENCE REVIEW. 
besides many illustrating the geology of other countries, par- 
ticularly North America, India, and Australia, the results of 
private labour, and of our colonial or foreign geological 
surveys. 
Such is the intimate connection between physical features 
and geological structure, that to the geologist a glance at the 
geological map of a country would enable him to obtain a very 
good idea of the character of its scenery. Denudation and the 
origin of scenery are most interesting subjects ; how hard and 
soft rocks are acted upon by rain, river, and sea ; how our bays 
and gulfs, islands and straits, cliffs and gorges, hills and valleys, 
were formed, are subjects now much discussed : they link 
geology with physical geography. Elevation gave the plan ; 
denudation did the work. Cfeology is but the “ physical 
geography of past ages we must interpret the past by the 
light of the present. Everything betokens change, and we 
cannot but sigh when we think of the vast amount of denuda- 
tion that is going on. At this rate, by atmospheric agencies 
alone, a mass of land as large as Em’ope must, according to 
a rough estimate of Professor Greikie, disappear in about 
4,000,000 years ! What use, then, will our geological maps be ? 
However, if we have thrown any light upon them, and pointed 
out some of their uses, so that they may be more fully appre- 
ciated at the present day, we may feel happy that our labour 
has not been lost. 
