THE BAGSHOT BEDS OF BAGSHOT HEATH. 485 



34. The Bagshot Beds of Bagshot Heath {a Eejoinder). By the 

 Rev. A. Irying, B.A., D.Sc, P.G.S. (Bead June 8th, 1892.) 



[Abridged.] 



The Author maintains that the northerly attenuation of the Lower 

 Sands and of the ' green-earth series ' between the two principal 

 brick-clays of the district is an established fact.^ He insists on the 

 value of the Wellington College well-section ^ as a vertical datum- 

 line, on account of its proximity to the northern outcrop (which is 

 not the case with the Goldsworthy section), and criticizes the argu- 

 ments recently put forward in favour of an alternative and very 

 doubtful sectional reading. But it does not stand alone, for the 

 well-section at the Bagshot Orphan Asylum ^ gives practically 

 the same sequence, and affords strong evidence of the thinning 

 northward of the above-named deposits. (Other instances cited 

 by the Author in ' Becent Contributions,'* &c., corroborate the 

 reading he has adopted.) The Goldsworthy section itself lends 

 strong corroborative evidence as to the value of the College well- 

 section. The evidence of attenuation in the direction of Bracknell 

 the Author reserves for the present. In his paper published in the 

 February number of the Society's Journal for the current year, Mr. 

 Monckton ignores the determinative value of stratigraphical align- 

 ment of the clays claimed as the basal clays of the Middle group 

 with clays of the same character seen cropping out from below the 

 ' green-earth series ' at no great distance.^ This evidence of strati- 

 graphical alignment must be allowed due weight when set against 

 evidence derived from such lithological characters as the presence of 

 pipe-clay, mica, and false-bedding.^ The Author considers that the 

 argument as to the fossil evidence is over-stated in the above- 

 mentioned paper.'^ 



After criticizing some of the remarks in Mr. Monckton's paper, 



^ See ' Eecent Contributions to the Stratigraphy of the Later Eocenes of the 

 London Basin': WeUington College (Bishop, 1891). 



^ Ibid., also App. Note A, p. 11 ; Quart. Journ. Geol. Soc. vol. xli. (1885) 

 p. 494 ; Mem. Geol. Surv. vol. iv. (App.) p. 425. 



^ See Mem. Geol. Surv. vol. iv. (App.) p. 537. 



^ Op. cit., Well-sections, cited in the Appendix, Note C, pp. 14, 15. See 

 also, for comparison. Sections K (p. 165), L (p. 165), M (p. 166), N (p. 166), 

 O (p. 171), P (p. 172), Q (p. 172), S (p. 174) of the Author's 1888 paper, in 

 Quart. Journ. Geol. Soc. vol. xliv. ; and fuller details of Sections P and Q in 

 Geol. Mag. for 1888, p. 411. 



[Extensive land-drainage works carried out by Rogers Field, Esq., O.E., on 

 the College Estate during the early part of this year (particulars reserved for 

 the present) furnish further confirmation for certain horizons. — July 1892.] 



^ See the Author's 1888 paper {loc. cit.), p. 164 (footnote), p. 167 (Sunning- 

 dale), pp. 174, 176, 183 (Additional Note on the Green-earth Series) ; also Geol. 

 Mag. for 1888, p. 413. 



6 See the Authors 'Recent Contributions, &c.,' Appendix, Note C (1), pp. 13, 

 14. 



■^ See Geol. Mag. for 1891, pp. 361, 362. 



