Vol. 55.] LIMESTON-E-KN-QLLS IN THE CEAVEN" DISTRICT. 327 



21. On LiMESToxE-KifOLLS in the Craven- District of Yorkshire 

 and elsewhere. By J. E. Marr, Esq., M.A., F.E-.S., E.G.S. 



(Eead April 26th, 1899.) 



[Plate XXIV.] 



Contents. 



Page 



T. Introduction 327 



TI. Greneral Structure of the Districr 328 



III. Natui-e of the Disturbances south of the Craven Faults. 331 



IV. Description of the Knolls near Cracoe and Settle, and 



Notes on Knoll-structure 338 



V. The Breccias 343 



VI. Comparisoii of the Deposits on both sides of the 



Faults 349 



VII. Natuie of the Movements which have affected the 



Rocks south of the Craven Faults 351 



VIII. Knolls of Limestone in other Areas 354 



IX. Concluding Eemarks 357 



I. li^-TRODUCTION. 



It is now many years since I began to pay attention to the frequent 

 and often sudden expansion of masses of limestone associated with 

 other deposits, and in the year 1888 I had the good fortune to 

 examine some of the remarkable limestone-masses of the Craven 

 district uuder the personal guidance of Mr. E. H. Tiddeman, to 

 whom we owe our knowledge of the structure of these masses. 

 Mr. Tiddeman has described and offered an explanation of these 

 structures in a series of papers, which, though brief, are remarkable 

 for their pithiness and lucidity, and reference to them will at 

 once enable anyone to understand the structure of the irregular 

 limestone-masses and the associated phenomena. 



Mr. Tiddeman's earliest account of these structures appears in 

 Eep. Brit. Assoc. 1889 (Newcastle-on-Tyne) p. 600, and further 

 descriptions by him will be found in the Excursion-guide for the 

 Leeds Meeting of the British Association in 1890 and that for the 

 London Meeting of the Geological Congress.^ A brief summary of 

 Mr. Tiddeman's views is published in an account of an excursion 

 to the Winterburn Valley,^ and the substance of his presidential 

 address to a Yorkshire scientific society, which largely deals with 

 the limestone-masses, appeared in the 'Craven Herald' for Jan. 

 29th, 1892. I shall endeavour to give a summary of Mr. Tiddeman's 

 work as published in these various papers, and shall refer to his 

 explanation of the origin of the irregular masses of limestone ard 

 the accompanying breccias. 



I Congres Geol. Internat. Compte-rendu, 4feme Sess. 1888 [publ. 1891] 

 pp. 319-323 & 324-329. 

 ■•* Trans. Leeds Geol. Assoc, pt, vi (1891) p. 111. 



