i6j. , CARBONIFEROUS. 



YOREDALE EOCKS AND UPPER LIMESTONE SHALES. 



The Yoredale Rocks were named by Professor Phillips from their 

 development in Yoredale (or Wensleydale) in Yorkshire, where 

 they consist of alternations of flagstones, gritstones, shales, seams 

 of coal, and limestones, altogether from 500 to 1500 feet in 

 thickness. 



The general characters of the Yoredale rocks may be thus stated. 

 In the upper part they consist of alternations of limestones, 

 sometimes siliceous, with sandstones, shales, and coal-seams ; 

 from 80 to 450 feet in thickness. In the lower part they consist 

 of alternations of flagstones, grits, shales, coal-seams, and three or 

 four beds of limestone ; from 250 to over 1500 feet in thickness. 



The limestones in the Yoredale rocks are remarkably persistent, 

 and the following lists, furnished by Mr. J. G. Goodchild, contain 

 the chief beds (in descending order) in the areas of Yoredale and 

 Alston Moor : ^ — 



Yoredale or Wensleydale. Alston Area. 



Crow Limestone. Fell Top Limestone. 



n J -D J T ■ .. Cracr Limestone. 



Red ceds Limestone. ^ -.J? j ■ 



Little Limestone. 



Main Limestone. Great or Twelve Fathom Limestone. 



Undersett Limestone. Four Fathom Limestone. 



Third Sett Limestone. Three Yard Limestone. 



Fourth Sett Limestone. Five Yard Limestone. 



Middle or Fifth Sett Limestone. Scar Limestone. 



Simonstone (Simonside) or Sixth Cockle Shell Limestone. 



Sett Limestone. Post Limestone. 



Hardra (Haidiow) or Seventh Sett Tyne Bottom Limestone (22 feet). 



Limestone. Jew Limestone. 



In Wensleydale the beds, together with associated grits, flags, 

 and shales, were grouped by Prof. Phillips into three divisions as 

 noted above: — 3. Cam or Upper Scar Limestone; 2. Hawes 

 Flagstone; and i. Black Limestone.^ 



Prof. A. H. Green observes that in the Yorkshire coal-field, 

 towards the top of the Carboniferous Limestone, the limestone 

 beds become thinner and more earthy, and the shale partings grow 

 more numerous, and a passage takes place upwards into the Yore- 

 dale Rocks. This group consists of dark shale, with beds of lime- 

 stone and sandstone. The limestones are usually thinly bedded 

 and more or less earthy, and frequently pass into calcareous shales. 

 In some cases a sharp line of division may be seen between the 

 groups : but the line drawn in various places is not likely to 



^ See also Sheet 102 N.E. of the Geological Survey Map, by C. T. Clough, and 

 others. 



- See West Yorkshire, by J. W. Davis and F. A. Lees, edit. 2, p. 7S ; T. 

 Sopwith, An Account of the Mining Districts of Alston Moor, etc., 1833. 



