244 ReiDort of the Non-Ferroiis Mining Committee. 



bathylith. Nevertheless the widespread occurrence in the shallower 

 mines of copper lodes is an encouraging feature from this point of 

 view, suggesting the existence below them of the tin, wolfram, and 

 arsenic zones. Several witnesses before the Coiiimittee asked for 

 financial assistance from the Government to assist explorations of 

 hitherto undeveloped deej)-level areas, and it may be said that 

 geological theory, so far as it goes, is favourable to the j^rospects of 

 a successful issue. 



Considerable space is devoted to a description of the projects 

 for the drainage to lower levels of the Halkyn-Llanarmon area in 

 Flintshire, which is considered to be perhaps the most important 

 area of lead and zinc ores in the whole country. Here the problem 

 is mainly geological, and depends wholly on the well-known water- 

 carrying capacity of the Carboniferous Limestone and the con- 

 sequent peculiar behaviour of the river system of that district. Here 

 the geology is perfectly simple, and the whole question is now mainly 

 financial ; if the project for the continuance of a new sea-level 

 drainage tunnel (which has been already started) can be carried out, 

 some extraordinarily rich and productive veins can be worked down 

 to a much lower level than at present, and a large addition made to 

 the home supply of lead and zinc for many years to come. This 

 seems to be pre-eminently a case for Government assistance. The 

 case for a similar scheme for the Wanlockhead and Leadhills 

 district appears to be less convincing, and neither the companies 

 concerned nor the royalty owners seem to display much enthusiasm 

 on the subject, owing to the immense capital expenditure necessary 

 for a 7 mile tunnel in hard Palaeozoic rocks. 



Another point of geological interest arises in connexion with the 

 lead-zinc deposits of Northumberland, Durham, and adjoining 

 counties, which are chiefly in the Great Limestone, and are 

 approaching exhaustion. Professor Louis suggested in evidence 

 before the Committee that trial should be made of the Melmerby 

 Scar Limestone as another jDossible productive horizon. This raises 

 an interesting question as to the influence of the Whin Sill on ore- 

 deposition in this neighbourhood, as to which little information 

 seems to be available. It is generally stated that in Derbyshire 

 lead-zinc ore-bodies are not found in payable quantities below the 

 toadstone, a presumably impervious igneous rock ; this suggests 

 a downward movement of the mineralizing solutions. On the other 

 hand, according to accepted modern theories of ore-deposition, 

 the movement should be upward and the ores found beloiv the igneous 

 rock. To one unacquainted with local conditions the question at 

 once suggests itself whether proper explorations have ever been 

 carried out below the toadstone, or whether the absence of ore 

 there is an assumption. With regard to the Whin Sill and the 

 northern area the same question is pertinent ; as is well known, 

 the Whin Sill is transgressive, occurring at different horizons in 

 the Carboniferous at different places, and it may be suggested that 



