WITH THE YORKSHIKE COAL-FIELD. 
99 
now in existence and operating on the surface of the earth were suf- 
ficient to account for all the past geological changes on the globe. 
The action of rain and frost in loosening the particles of soil and 
rock, their removal and carriage to more or less distant areas by 
streams and rivers, the abrading action of the waves, were agencies 
constantly at work and capable of producing gTeat geological changes. 
These operations during untold ages removed mountains, and reduced 
the land surfaces beneath the level of the sea, whilst the material so 
removed went to form new areas of land. The successive alternations 
of sea and land could be traced in the sequence of the rocks ; and the 
power of volcanic action was recognized as frequently assisting in the 
elevation of an old sea bottom to form dry land. The frequent 
occurrence of granite and other crystalline rocks was accepted as 
proof of this action. The Huttonian theory, though fixed on so solid 
a basis that it may be regarded as the groundwork of every succeed- 
ing speculation and as the foundation on which the superstructure of 
modern geological science has been erected, took no cognizance of the 
fossil remains of animals and plants contained in the rocks, and it re- 
mained for William Smith to discover that each stratum of rock has its 
characteristic and peculiar fossils. He was a native of Oxfordshire, and 
was trained to the profession of a land surveyor and civil engineer. 
During his early years he collected fossils from the Oolitic rocks, near 
Bath, and his practical and thoughtful method of studying them, 
led him to the conclusion that each stratum was characterized more 
or less by fossils peculiar to it, and that these did not extend to the 
beds above or below. Whilst maturing this discovery his professional 
duties called him to Yorkshire, and his attachment to geological 
science, soon led to the investigation of the secondary strata of this 
great county, and he was surprised and delighted to find that his 
observations in the j\Iidlands were confirmed and substantiated in 
Yorkshire ; he found the same gToups of fossils in their respective 
beds of rock, shale, or limestone, and came to the conclusion that 
those beds extended across the country from Dorsetshire to 
Yorkshire, and that they could everywhere be distinguished by the 
fossils they contained. Visits to all parts of the country soon con- 
vinced Smith that his discovery applied to all the stratified rocks ; 
