The Metallogeny of the British Isles

I. I ntroduction . T he recent development of the geographical method of studying ore-deposits is due to Prof. L. de Launay, who first pointed out its application in 1897. His later works on this plan include examinations of the ore-deposits of Africa, Italy, and Siberia. His object is to delineate the various regional types of ores, and to show their intimate genetic relation with tectonics and with petrographic provinces, the regional types being termed ‘metallogenetic provinces’. The same method has been applied by Dr. J. Malcolm Maclaren in his ‘uriferous provinces’. We have thus, in the science of ore-deposits, the application of methods analogous to those exemplified in Suess's ‘Antlitz der Erde,’—methods which aim at correlating detached observations, and bringing our knowledge of the ore-deposits of an area into relation with our knowledge of its geological structure. In the present paper an endeavour is made to work out the distribution of ore-deposits in the British Isles, and to determine the relationship of the ores to the tectonics of the country, and to the distribution of igneous rocks therein. Prof. de Launay's nomenclature has been followed, and I wish here to express my thanks to him for his kindness in corresponding with me on the subject. The modern analytical classifications of ore-deposits, while nominally on a genetic basis, involve, as subdivisions, factors of varying importance—genesis, form, mineralogy, and structure. The essential and accidental features are liable to be confused, and the latter unduly emphasized. Further, there is a tendency to make the deposits,