430 Correspondence — John T. Stohhs. 



C0iai2,ESi30iTnD-£]iNrc:E. 



THE 'YOREDALE' EOCKS OF NORTH DERBYSHIRE. 



SiE, — I was pleased to see in your last issue Mr. J. A. Howe's 

 protest against the application of the term ' Yoredale ' to the series^ 

 of rocks which are found between the Millstone Grits Series and 

 the Massif of North Derbyshire. 



The name ' Yoredale ' was first used geologically by Phillips in 

 his " Geology of Yorkshire," pt. ii, pp. 36-7, and he leaves no doubt as 

 to the character of the group of rocks to which he applied the term. 

 " We shall choose as a general standard of refei'ence for this complex 

 series of rocks, that district where this character of complexity is 

 the greatest. The upper end of Wensleydale is adopted. The total 

 thickness of the Upper Limestone Series in this situation is about 

 one thousand feet, and it consists of the following groups — constituting 

 what I term the Yoredale Series." Hereafter follows the succession 

 of the beds from the Main Limestone to the shales below the 

 Hardraw Scar Limestone of that district, a series having perfectly 

 definite lithological and palseontological characters, and anyone wha 

 has visited the vale of the river Ure will have been delighted with 

 the ' country ' selected as the ' type.' 



Unfortunately for students, however, Phillips also described, as 

 belonging in part to the Yoredale Series, another and widely difierent 

 development of rocks, whose position had evidently puzzled him 

 greatly, for their description, with peculiar inconsistency on the 

 author's part, comes under the heading " Millstone Grit Series in 

 Craven " (p. 72). It is this development whose correlative occurs 

 in the Peak District, but which is totally unrepresented in the 

 Yoredale area, and which, for that reason, it is wrong to denominate 

 'Yoredales.' Farcy's term, 'the limestone-shales,' although by no 

 means an ideal name for the group, has right of priority, and at 

 any rate possessed the negative virtue of causing no confusion or 

 misconception as to the character or position of the measures ; nor 

 did it commit the user to any theories. 



The series under discussion is a very important one, whose 

 thickness in places is 1500 feet ; it gives to the localities of its 

 development surface features which are totally different to those 

 of the typical Yoredale country : it contains a characteristic fauna ; 

 and it is worth a distinctive name. 



Familiarity with both types leads me to commend the wisdom 

 of selecting such a name as ' Pendleside Series ' for this group, 

 and I believe the distinction thus marked cannot fail to be of service 

 to workers in the science. John T. Stobbs. 



DuNELiN, Basford Park, Stoke-on-Trent. 

 2\stJuhj, 1904. 



