234 THE JMCTdU COAL FIELD — POOLE. 



open to the public and explorations became t,^eneral the coal 

 prospector vvho in his search met with rocks of a red colour 

 stopped working in that directi(3n convinced that he had reached 

 a)i hoi'izon beyond the C(jals of workable thickness. In practice 

 he was right ; no good seams are immediately overlaid by red 

 rocks in this field. This experience of the miner perhaps led the 

 geologist who followed to infer that all the red rocks, so called, 

 of the district are necessarily older than the coal measures ; at 

 any rate they were so classed, except by Sir William in McBean's 

 areas. 



The red rocks immediately south of Stellarton railway station 

 and those about French's tunnel on the Middle river are so p-iven 



CI 



by the Survey, V)ut they are now believed to be of the same 

 horizon as beds in undoubted coal measures, and the faults neces- 

 sarily assumed to separate the two divisions have been proved,, 

 it may be said, to be non-existent. 



In 1852 Mr. H. Poole mentioned the radical change that takes 

 place in some of the strata when traced but a short distance ; a 

 change the more noticeable wdien the beds are followed from the 

 centre to the margin of the field. Shales become more and more- 

 arenaceous until ultimately they pass into beds of sandstone even 

 with intercalated conglomerates ; black fireclays become l.)rown 

 and ultimately cold grey ; and coals become coarse, then black 

 fireclays and finally thin out. Boreholes at Westville put dov\n 

 from the upper to prove the (juality of expected lower seams 

 passed through into red rocks without finding the equivalents of 

 seams underlying in order to the eastward at e(jual depths. 



The coal of McLeod's pit on the east side of the East river, 

 which is on the attenuateil extension of the main seam, it is said 

 direct!}^ overlies red rocks. This change of colour and character 

 accompanies an approach to the margin of the basin ; and if the 

 present margin approximates at all to the margin of deposition, 

 which is the present conclusion, a very decided difference in the 

 appearance and quality would naturall}^ be expected in those- 

 portions of any beds which bore this relation to one another. 



Retl rocks occur in strata both above and below the coal 

 measures, and slight exceptions have been seen in these measures. 



