217 



W)t Blultitng of tljc ^nljgsi^tvf Htmcstonr. 



By George Fletcher, F.G.S. 



N previous Journals I have dealt with the origin of 

 Derbyshire scenery. In the present paper it is my 

 intention to trace the origin of one of the rocks whose 

 varied forms give rise to scenery. My earlier papers dealt with 

 the cause of the external form assumed by rocks, the present 

 one deals with the origin of the rock itself. Investigation teaches 

 us that matter, like energy, is constantly undergoing transfor- 

 mation — passing through a cycle of changes. The matter which 

 constitutes our limestone rocks is no exception, and I propose 

 iiere to deal with this fleeting phase of its transformations. 



The Derbyshire limestone is of great interest, both from 

 economic and purely geological standpoints. It is rich in mineral 

 lodes and veins yielding ores of lead, zinc, (S:c., valuable building 

 stones and ornamental marbles. It forms an immense mass of 

 very great but unknown thickness, during the formation of which 

 several submarine volcanic eruptions took place, the ejected lava 

 forming the beds of loadstone which are found interstratified with 

 the limestone. Looked at as a whole, the limestone area forms 

 part of a great fold or anticlinal, the axis of which runs from north 

 to south, forming the southern portion of the great Pennine anti- 

 clinal. From above this central area the millstone and newer rocks 

 have been eroded, leaving the limestone exposed at the surface. 



The limestone differs widely in different districts, and at different 

 levels. In the upper portion it is thinly bedded and contains 

 layers and nodules of chert, below which is a great thickness of 



