EXPLANATION OF PLATE 67. 106 



resulting from these Interruptions of the continuity 

 of the strata are pointed out in pp. 543, 544. 



A large portion of the surface of these strata 

 near Newcastle is covered with a thick bed of 

 diluvial Clay interspersed with Pebbles, in the 

 manner represented at the top of this Section. The 

 effect of this Clay must be to exclude much rain- 

 water that would have percolated downwards into 

 the Coal mines, had strata of porous Sandstone 

 formed the actual surface. 



Plate 67. V. I. p. 559. 



Fig. 1. represents the case of a valley of Denudation in 

 stratified rocks, terminated abruptly by a cliff on 



copies of his most important plans and sections, accompanied by 

 written documents, of the under ground workings in the Collieries 

 near that town, in which all those spaces are carefully noted, from 

 whence the Coal has been extracted. Every practical Miner is too 

 well acquainted with the danger of approaching ancient workings in 

 consequence of the accumulation of water in those parts from which 

 Coal has been removed. The sudden irruption of this water into a 

 mine adjacent to such reservoirs is occasionally attended with most 

 calamitous and fatal results. See History of Fossil Fuel, the Col- 

 lieries and Coal Trade, 1835. P. 249 et seq. 



The dictates of humanity which prompt us to aid in the preserva- 

 tion of human life, no less than the economical view of rendering 

 available at a future time the residuary portions of our beds of 

 Coal, which will not now repay the cost of extracting them, should 

 induce all proprietors and other persons connected with Coal Mines, 

 and especially Engineers and Coal Viewers, to leave to their succes- 

 sors a legacy, which will to them be precious, by preserving minute 

 and exact records of the state of the coal in their respective districts. 

 It can, however, scarcely be expected, that such measures will be 

 generally and systematically adopted throughout the many Coal 

 fields of this country, unless the subject be legislatively taken up by 

 those official persons, whom it behoves, as guardians of the future 

 welfare of the nation, to institute due measures, whilst the opportu- 

 nities exist, for preventing that loss of life and property, which a 

 little attention bestowed in season, will preserve to posterity. 



