162 



PROF. T. T. GROOM ON THE GEOLOGICAL [May 1 899, 



blue loam (M 151)/ evidently resulting from the decomposition of 

 fine argillaceous sandstone. The best section seen of the May Hill 

 Beds was exposed in making a cistern (M 151 & 152) near the 

 Powlet Farm cowshed. In this 2 feet of reddish-yellow soil passed 

 down into 3 feet of blue clay, the upper part of which contained 

 derived fragments of Holly bush Sandstone; the lower fragments were 

 of argillaceous sandstone only, showing all stages of decomposition 

 into blue clay : below this, a thickness of 3 feet of disintegrated 

 purple sandstone was seen. The junction of the clay and purple 

 sandstone was an undulatory surface dipping mainly northward, but 

 sometimes north-eastward, at an angle of 10° or less. Both beds 

 furnished fossils ; among these I recognized the following : — 



Atrypa reticularis, Linn. 



Fe7itamerus sp. 



StricJdandinia lens {?) Sow. 



Pterinea sp. 



G-asteropods. 



Tentaculites anglicus, Salt. 



Orthoceras sp. 



Encrimirtcs piinctahis, Briinn. 



Crinoids. 



Lindstroemia stibduplicata, M'Coy. 

 L. s. var. crenulata. 

 Favosites asper (?) d'Orb. 

 Leptocoilia hemisph<srica, Sow, 

 8tropliomena antiqicata, Sow. 

 Orthis calligramma, Dalm. 

 Orthis sp. 



Spirifera elevata, Dalm. 

 Spirifera crispa, His. 



The existence of Llandovery rocks in the neighbourhood of Fowlet 

 Farm was known to Phillips, HoU, and Symonds. Phillips ^ said : 

 'There are beds of true Caradoc sandstone (No. 6), with fossils in 

 tolerable plenty, near Fowlet Farm, thrown down by some obscure 

 but powerful displacement, or deposited unconformably.' HoU ^ and 

 Symonds* regarded the patches here, and to the north, as outliers 

 resting unconformably upon the Cambrian rocks. 



That these patches are in reality blocks faulted into the Cambrian 

 is evident, first, because not only do the basaltic ridges and inter- 

 stratified shales strike directly towards the sandstone in such a 

 way that it cannot be supposed that the latter overlies the shales 

 (fig. 21, p. 160), but the sandstone itself appears to strike up against 

 the shales ; secondly, the rectilinear boundaries point towards the 

 same conclusion; and finally, to all appearance, the Llandovery Beds 

 in the escarpment to the west dip in approximately the same 

 direction, and probably at nearly the same angle, as the underlying 

 Grey Shales (see p. 167), wherefore the basal beds of the escarpment 

 would pass far above the sandstone of the patches (fig. 13, p. 144). 



The geological structure of that part of the district which lies 

 between the igneous bands of the Grey Shales and the May Hill- 

 Sandstone patches of Fowlet Farm and Pendock's Grove is by no 

 means clear. The chief exposures consist of igneous rock. A well- 

 marked circular boss of basalt (M 104) occupies the angle between 

 the two patches of sandstone, and a smaller boss (M 124 & 125) is 

 seen west-north-west of this. In the road, 30 yards south-south-east 



1 [Marked 157 on the map, PL XIII.] 



2 Mem. Geol. Surv. vol. ii (1848) pt. i, p. 54. 



^ Quart. Journ. Geol. Soc. vol. xxi (1865) p. 94. 

 ^ Proc. Geol. Assoc, vol. iii (1873) p. 269. 



