VOL. XIV. (1) MENDIP ARCHIPELAGO 69 
| submerged by further subsidence, and thus the Mesozoic 
geography of the Mendip archipelago came to an end. 
APPENDIX. 
The Pre-Planorbis and Lower Lias Deposits of Broadfield 
Down, near Bristol. 
The age of the deposits of this district seems to have 
been a matter of much doubt. In the older geological 
maps the post-Triassic Mesozoic deposits of Broadfield 
Down’ were coloured as “ Alluvial.”* De la Beche, in the 
early days of the Geological Survey, traversed this district 
and embodied the results of his investigations in his 
classic work “On the Formation of the Rocks of South 
Wales and South Western England.”> He commented 
upon the peculiar lithic characters of the strata here 
presented, remarking that “in places the Lias was con- 
glomeratic, and partook of the nature of the Sutton 
Stone,’* and since he considered the Sutton Stone to be 
“‘a whitish variety of Lias” he apparently considered the 
Broadfield Down Rock to be of a similar nature. Tawney 
observed that the Southerndown Series seems to have 
been deposited in an area of depression upon the 
Carboniferous Limestone, and the same may be said of 
_ the analogous beds of Broadfield Down.5 He further 
noted that the strata of this district were conglomeratic 
in places, enclosing Carboniferous fossils, and were 
_ “precisely similar to the Sutton Stone.” 
; 1 A district west of Dundry Hill; the area here described being contained in Sheet 
xi, N.E. Somerset (6 in. scale). 
2 Moore, Quart. Journ. Geol. Soc., vol. xxiii. (1867), p. 504. 
3 Mem. Geol. Surv., vol. 1. (1846), pp. 1-296. 4 Ibid, p. 276. 
5 Quart. Journ. Geol. Soc., vol. xxiii. (1867) p. 79. 
