INTRODUCTION. 
-Oefore engaging in the study of this Volume, it may be useful 
to the reader to know what is the object it professes to attain, and 
what have been the means and endeavours of the Author for the ful- 
filment of his plan. A systematic view of the Mountain Limestone 
formation in Yorkshire especially, and in the North of England gene- 
rally, under all its varied relations, is here attempted for the purpose 
of establishing a common standard, and local truths, to which the phe- 
nomena of analogous rocks in other districts may be compared. 
It may reasonably be demanded why is the Yorkshire series of 
mountain limestone selected for such an object, and how has it hap- 
pened that the Author of this Volume has become responsible for 
the execution of such a labour. The Book itself will, it is believed, 
supply a satisfactory answer to the first inquiry by shewing that no 
more comprehensive type of mountain limestone can be found in 
England than that which exists in Yorkshire, under circumstances 
of physical geography remarkably favourable to exact research. In 
consequence of this clear and complete development, the method of 
variation, by which the simple type of Derbyshire passes into the 
complicated group of Northumberland, is clearly traced in Yorkshire; 
the numerous organic exuviae have been successfully collected ; and 
the effects of great subterranean disturbances correctly appreciated. 
The laws of these phenomena, rightly determined in this particular 
region, will indicate the problems which remain to be solved in other 
districts, before the beautiful fragments of geological truth, which are 
