398 ME. L. EICHAEDSON ON THE INFEEIOE OOLITE [Nov. I907, 



overgrown by feathering woods ; while the geologist observes, as a feature of 

 peculiar interest in their precipitous escarpment, the actual contact of the hori- 

 zontal bed of Inferior Oolite resting on the truncated edges of strata of Mountain 

 Lime[stone], thrown up in an angle of from 50 to 60 degrees. This line of 

 contact is sometimes perfectly level for a considerable distance (as if the edges 

 of the Mountain -Limestone strata had been rendered smooth by some 

 mechanical force abrading them previously to the deposition of the Inferior 

 Oolite), but in other instances it is rugged and irregular ; sometimes the contact 

 is mai-ked by a breccia of fragments of the older, cemented by the newer rock, 

 but this is by no means constant.' 



Sir Henry de la Beche noticed the ' marked even surface ' of the 

 Carboniferous Limestone ; borings 



' of two kinds, one long, slender, and often sinuous, extending several inches 

 into the Carboniferous Limestone, the other entering tbat rock a short distance 

 only ' ; and ' on the top of the hill between Holwell and Leighton oyster- 

 shells, of the date of the Inferior Oolite, adhering to the old surface of 

 Carboniferous Limestone. . . .' (Mem. Geol. Surv. vol. i, 1846, p. 289.) 



Mr. W. H. Hudleston is quite correct in assigning a Ch/jieus-Giit 

 age to the Inferior Oolite which rests directly upon the Carboni- 

 ferous Limestone in the well-known section in Vallis Vale x ; and 

 Mr. H. B. Woodward rightly recognized that, on INunney Common 

 and near Little Elm, there are beds ' like the Doulting Stone.' 2 



It is very doubtful whether the Upper 2'rigonia-Grit equivalent 

 ever extended right across the eastern end of the Mendip Hills : in 

 most places the Doulting Stone rests directly upon the Carboniferous 

 Limestone. I have only observed rock, which is most likely of 

 Garantiance hemera, at two places in Whatley Combe — in the large 

 quarry to the north of the inn at Holwell, and at Moore's ' Marston- 

 Koad section.' In that near the inn, the probable representative of 

 the Upper Trigonia-Giit is an intermittent bed (measuring up to 

 6 inches in thickness, and full of Acanthothyris spinosa), which rests 

 upon a level, oyster-covered, and bored surface of highly-inclined 

 Carboniferous Limestone. The Upper Trigonia-Grit also has a water- 

 worn and oyster- covered upper surface, and this rather upholds the 

 view that it is that deposit, because, as already mentioned, the top- 

 portion of the Upper Trigonia-Giit often exhibits these phenomena, 

 which point to a non-sequence. In the present case, the Dundry 

 Freestone and apparently the Upper Coral-Bed are wanting, the 

 Doulting Stone resting non-sequentially upon the Upper Trigonia- 

 Grit. Some of the marly material which parts these last two 

 subdivisions was sent to Mr. Charles Upton to be washed, on the 

 possibility of its containing the zonal fossil Spiriferina (?) oolitica ; 

 but neither this nor any other micro-organism was found. From 

 this quarry I have fragments of the ammonites Parkinsonia aff. Par- 

 Jcinsoni (Sow.) and P. densicosta (Quenstedt). They indicate Truellii 

 hemera, wherefore if they came from the Doulting Stone, then 



1 ' Gasteropoda of the Inferior Oolite ' Monogr. Palseont. Soc. pt. i (1887) 

 p. 54. 



2 'The Jurassic Eocks of Britain — The Lower Oolitic Eocks of England 

 (Yorkshire excepted) ' Mem. Geol. Surv. vol. iv (1894) p. 90. 



