Mr. M. Dunn on the Sinking of Preston Grange Engine Pit. 285 



1. In case of cutting through Dykes, the troubled Stone is not un- 

 frequently found to convey water. 



2. If so large a proportion of Coal should be wrought away as to 

 bring on a Creep, or Thurst, and thereby break the stratification be- 

 tween the part tubbed-off and the Coal. 



3 The working away of the mine so near to the old colliery, as to 

 enable the water to filter through the Stone or Coal. 



Although a principal working will be carried on under the Frith of 

 Forth, I am under no apprehension on that head, for although so near, 

 and where the stratification is laid bare along the sea-shore, we have 

 never had the least leakage of sea-water. 



As the colliery is intersected by a Whin Dyke, of from 15 to 20 

 yards wide, running within 200 yards of the shaft, and through which 

 the north levels are intended to be carried, that question will, in due 

 time, be solved, as well as the state in which this Dyke exists so far be- 

 low the surface. 



In conclusion, I beg to state that I intend, at my earliest convenience, 

 to present the Society with the result of my observations upon this part 

 of the Coal-field of East Lothian, which seems replete with interesting 

 matter. 



Since this paper was read before the Natural History Society, I have 

 had the honour of receiving (on the 20th June) from Sir Thos. Dick 

 Lauder, Bart.), the Chairman of the Edinburgh Society of Arts, their 

 first Silver Medals. 



