400 ME. L. EICHAKDSOIS- OTST THE INFEEIOE OOLITE [NoV. I907, 



resting thereon unconformafrly, are Inferior-Oolite limestones. 

 These facts show that at. this locality, at all events, the sequence 

 from Lias to Inferior Oolite is incomplete, and that movements 

 along the Mendip axis were not infrequent in early Jurassic times. 



On Nunney Common the Doulting Beds rest directly Upon the 

 Carboniferous Limestone. At the northern end of the Common, 

 where the road forks, the surface of the limestone has been laid 

 bare, and is seen to be much bored and oyster-covered. 



It is not necessary to describe every section in the neighbour- 

 hood of Vallis Yale, because in all the succession is much the same. 

 There does not seem to be any deposit referable to the Upper 

 Tric/onia-Grit between the Doulting Beds and the Carboniferous 

 Limestone in this area ; in all the sections that I examined the 

 Doulting Beds — ' beds,' as Mr. Hudleston rightly observed, ' of the 

 age of the Clypeus-Grit' — rested directly upon the Limestone, except 

 near Hansford Mills, where they reposed upon Bhgetic beds. 



The surface of the Carboniferous Limestone is remarkably even. 

 If one stands upon the platform formed by this rock after the 

 Inferior Oolite has been stripped off by the quarrymen, and looks 

 across the flat-bottomed valley, with its mural sides, at the other 

 extensive quarries, one cannot repress a feeling of astonishment at 

 the excessive evenness of the plane of erosion. This surface is 

 riddled with annelid- and, less commonly, with Lithophagus-bormgs, 

 and in places is strewn with oysters. Many years ago De la Beche 

 noticed these phenomena, and his sketch of the section near the 

 bridge in Murdercombe is well known (Mem. Geol. Surv. vol. i, 1846, 

 p. 288). 



The following section was measured in the quarry on the east 

 side of the spur of high ground that runs southward and forms the 

 western side of Vallis Yale — in fact, separates the Vallis proper 

 from the valley which bends round towards Elm. 



(A) Section in Vallis Vale. 



Thickness in feet inches. 

 Doulting Beds. 1. Oolitic limestone, thinly bedded or flaggy; 



inaccessible, but estimated at 8 to 10 feet . 9 



2. Limestone 1 2 



3. Bubble: to 2 inches 1 



4. Limestone, massive 1 9 



5. Bubble : to 2 inches 1 



6. Limestone, massive 1 4 



1 7. Bubble : 2 to 4 inches 2 



8. Limestone, massive, more rubbly at the top 



and bottom, coarsely oolitic 2 6 



9. Clay-band : to 2 inches 1 



10. Limestone, massive, harder than the beds 



immediately above and below it, and 

 therefore more conspicuous, standing out. 

 Ctenostreon pectiniforme (Schloth.), very 

 common, Trichites (fragments), Pentacrinus- 

 ossicles, Serpula cf. Umax, Groldf., Hhyn- 

 chonella hampenensis, S. Buckman, ? Eh. 

 subtetrahedra, Dav. Fragments of chert 

 occur not infrequently in this bed 1 7 



