Correspondence. 47 



Look at a river-cliff, formed of drift ; what destruction does a flood 

 to it ? A mere bagatelle, unless there has been a frost previously, 

 and then tons of debris fall, to be earned away by the river. 



The work done by Eain and Elvers is perceptible in centuries, 

 while the work done by Frost in this country (not to go to its large 

 work-shop in the North) is perceptible after every winter. 



The Sea acts in a similar manner. Its years' work is clearly seen 

 — aye, even the work of a single tide. We know that Eain has done 

 very little work in this country since the Grlacial period, as the rocks 

 forming the bottom of all the large valleys and Cooms, and of most 

 Allies or ravines, are Ice-dressed, and yet we are to believe that Eain 

 has cut out those valleys instead of ice ! while ice is doing exactly 

 similar work farther North at the present day. 



The same way with the sea. If we examine the work done by 

 the sea we find that it cuts away soft or homogeneous rocks, such 

 as shales or limestones, while hard rocks, such as traps and grits, it 

 leaves standing as Carrigs, Carrigeens, or Illauns ; and if we go inland 

 we find hummocks, Carrichs, or crags and liillocks formed of bosses 

 of traj) or some other hard kind of rock protruding out from moun- 

 tain sides or standing up in undulating plains ; the surrounding 

 country in every case being of a much softer rock ; and yet we are 

 to believe that the mountain slopes and the undulating plains were 

 formed by Eain and Elvers, and not by marine denudation. 



I do not mean to say that Eain and Elvers have not done some 

 work, but what I do say is that they are only some of the minor 

 workers — that they do a little work on their own account— but that 

 their place in nature is that of "Carriers" to remove the debris which 

 other agents (principally the Sun and Frost) have formed. 



Yours truly, 



G. Henkt Kinahan. 



OuGHTERABD, Ikeland, Bcc. 2nd, 1865. 



A BUENING COAL-SEAM. 



A CoEEESPONDENT, " E. N.," states that "at Bradley, a small 

 village near Bilston in Staffordshire, a Coal-bed has been burning 

 for half a centiuy," and enquires if this be true, and "whether there 

 are no other means, except 'flooding the pit,' to extinguish the 

 fire and arrest the useless destruction of valuable fuel." 



On referriag to A. K. Johnston's Dictionary of Geography (Lon- 

 don, 1853) we find a statement to the same effect. We shall be 

 glad if any correspondent will inform us whether the seam be still 

 burning, and what is the depth of the mine. 



We recorded (Geological Magazine, vol. ii. p. 336) an instance 

 of an outcrop of Coal of Miocene Tertiary age on the Mackenzie 

 Eiver, noticed on fire, as long ago as 1785, by Sir Alexander 

 Mackenzie, and again by Sir John Eichardson, in 1849 ; but we did 

 not think that such destruction was allowed to take place in England, 

 and cannot suppose it to be irremediable. — ^Edit. 



