NATURAL HISTORY 



TRANSACTIONS 



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NORTHUMBERLAND AND DURHAM. 



A NEW FLORA 



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NOETEUMBEELAND AND DUEHAM. 



PART I. 

 GEOLOGY, CLIMATOLOGY, AND PHYSICAL GEOGRAPHY. 



CHAPTER I. 



GEOLOGY, BY GEORGE TATE, F.G.S., &c. 



As the piincipal object of this memoir, on the geology of North- 

 umberland and Durham, is to supply data to help the botanist to 

 see how far the Flora of these counties is influenced by their geo- 

 logical structure, I shall especially direct attention to the mineral 

 character and range of the various rock formations. JN^everthe- 

 less, the consideration of more general questions will not be alto- 

 gether avoided ; the classification of groups of strata, according 

 to age, will be attempted; their organic history will be indicated; 

 and as relative elevation itself gives a character to vegetation, it 

 will be necessary to notice in passing, the disturbing agencies 

 which at different periods have rent the strata and lifted up our 

 mountains, or left an impress on the general contour of the surface. 



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