Sorace B. Woodward — The Chalky Boulder-clay. 487 



Eailway), have trenched the country in a north-and-south direction, 

 and very fine sections of Chalky Boulder-clay were exposed between 

 Catesby and Quainton Road, near Aylesbury. The Middle Lias 

 fossils were noteworthy ingredients of the Boulder-clay in the north, 

 and those of the Oxford Clay in the south. In none of these 

 cuttings were there exposed any very large boulders or " cakes " 

 of Secondary rock. 



Chalky Boulder-clay occurs in various parts of Warwickshire. It 

 was recognized near Eugby by S. V. Wood, jun.,^ and in other 

 localities by the Eev. P. B. iJrodie^ and by Mr. W. Andrews.^ 

 T. G. B. Lloyd ^ observed purple-coloured Boulder-clay containing 

 Chalk, etc., on the Lower Lias area in north-east Warwickshire ; 

 and it is likely that in this county, as elsewhere, coloured clays from 

 the New Eed Series have been disseminated with other materials 

 in the Boulder-clay. 



The most distant evidence of Boulder-clay in the south-western 

 region is that to which attention was directed in 1853 by Mr. G. E. 

 Gavey.^ The Drift, comprising Boulder-clay, gravel, and sand, was 

 exposed in the railway-cuttings at Aston Magna and Mickleton, and 

 at the time Mr, E. F. Tomes obtained glaciated Chalk from this 

 Drift." In connection with the discovery, it is interesting to note 

 that pebbles of hard red and white Chalk were found by Buckland 

 in 1821, to the south-east of Shipston-on-Stour.'' 



It may be remarked that the " Boulder-clay " to which Mr. W. C. 

 Lucy has called attention as occurring on the Cotteswold plateau, is 

 simply clay with " Northern Drift " pebbles. It occurs in pockets 

 or fissures of the Inferior Oolite here and there, but in itself it affords 

 no evidence of glaciation. Moreover, the so-called " Northern Drift " 

 in the lower portions of the Severn Vale is reassorted, and no doubt 

 derived its erratic pebbles from Boulder-clay in the upper parts of 

 the Severn drainage-area. 



To the north-west of Leafield, and at Combe near Woodstock, the 

 higher elevations of Oxford Clay have a thin covering of soil with 

 pebbles of quartz and quartzite. This gravelly soil lies irregularly 

 on the clay, and penetrates it in hollows to a depth of three or four 

 feet, having no doubt descended in cracks which have opened in the 

 clay during very dry weather. Drift of this character affords no 

 evidence of glaciation. 



That the Cotteswolds themselves have not been glaciated, is shown 

 by the thick accumulations of oolitic rubble which flank their slopes. 

 Even the Bredon outlier of Inferior Oolite exhibits at the surface 

 30 or 40 feet of rubble. The rock, indeed, is irregularly weathered, 

 and the resulting gravelly detritus contains in its midst isolated 



1 Quart. Journ. Geol. Soc, vol. xxvi, p. 224, and Geol. Mag. 1870, p. 18. 



^ Quart. Journ. Geol. Soc, vol. xxiii, p. 209, and Rep. Brit. Assoc, for 1865, p. 49. 



3 Proc. Warwickshire Nat. Club for 1884, 1885, p. 32. 



* Quart. Journ. Geol. Soc, vol. xxvi, pp. 205-6. See also A. H. W. Ingram, 

 ibid., XXXV, p. 678. 



= Quart. Journ. Geol. Soc, vol. ix, p. 29. 



* Proc. Cotteswold Club, vol. vii, p. 60. 



' Trans. Geol. Soc, vol. v, p. 618; ileliq. Diluv., 1823, p. 250. 



