301 REPORT — 1894. 



Sfonesfleld Slate. — Beport of the Committee, consisting of Mr. H. B. 

 Woodward {Chairman), Mr. E. A. Walford (Secretari/), Professor 

 A. H. Green, Dr. H. Woodward, and Mr. J. Windoes, appointed 

 to open further sections in the neighbourhood of Stonesfield in order 

 to show the relationship of the Stonesfield Slate to the underhjing 

 and overh/ing strata. (JDravm np In/ Mr. Edwix A. Walford, 

 Secretari/.) 



The basement beds of the Great Oolite in the Midlands and in the south- 

 west counties of England have been hitherto supposed to be well defined. 

 For in all the records of the many writers on this geologic subdivision, 

 to the Stonesfield Slate has been assigned the line of separation from 

 the Fuller's Earth or Inferior Oolite, or, where the Stonesfield Slate is 

 absent, as in the extreme west, to the Minchinhampton beds has been 

 given the same position. Undue prominence has been given to so incon- 

 staut a series of beds as the Slate, as much from the ease with which 

 fossils for its study have been collected as from the varied character 

 of the fauna and flora found in it. From the days when the finding of 

 the mammalian remains in the Slate called the attention of geologists 

 prominently to it, every text-book of geology has found a place for it at 

 the bottom of the Great Oolite limestones. Though, however text-books 

 and papers have defined the lower boundary of the Great Oolite so clearly, 

 tlie officers of the Geological Survey in their work in the neighbourhood 

 of Stonesfield found the lines so difficult to define that it became neces- 

 sary, where the Slate had disappeared, to adopt an intermediate colour- 

 ing, a kind of no-man's-land. Since then an argillaceous stratum, ' the 

 Rift bed,' has been recognised as the lowest of the Great Oolite beds in 

 tlie Banbury and Hook Norton area. 



The endeavour of the work, for which the British Association made a 

 money grant in 1893, has been to ascertain the thickness and composition 

 of the beds underlj'ing the Slate, for hitherto no account of these beds has 

 been obtainable. Professor Ed. Hull's record ' of 70 feet being the only 

 assumed thickness of the Great Oolite, and to this he adds 30 feet for the 

 Inferior Oolite. Though their thicknesses seem to be over-estimated, no 

 correction or account of a series of I'ocks so important has since then been 

 written. Nearer Chipping Norton, however, Mr. J. Windoes, Mr. W. H. 

 Hudleston,^ and your Secretary ^ have worked at some of the debatable 

 beds above the Clypeus grit, one of the highest of the Cotswold divisions 

 of the Inferior Oolite. 'To the bulk of these beds has been given the name 

 of the ' Chipping Norton Limestone ' by Mr. Hudleston,^ and though the 

 beds have not been reached in the section, they may be seen in the lane 

 sections and near the spring on the banks of the Evenlode, south of 

 Stonesfield. Your Secretary in 1892-93 sank a shaft near Ditchley, Oxon, 

 to find out the true position of the Slate beds there ; but of this an account 

 will be published elsewhere. 



The progress of the work, so far, at Stocky Bank, Stonesfield, has 



' Repiirt Brit. Amoe., 1860, p. 82 (Sectional Proceedings). 

 - W. H. Hudleston. Proc. Geol. Assoc, vol. v. No. 7. 



' E. A. Walford. ' On the Relation of the so-caiied Northampton Sand of N. Oxon 

 to Clypeus Grit,' QJ.O'.S., vol. xxxix. p. 285. 



