58 MR. L. RICHARDSON ON THE RH.ETIC OF [Feb.* I9I I, 



All the authors who have described this section have noticed a 

 bone-bed at the base of the Pteria-contorta Shales ; but, while the 

 type that Brodie saw was an ossiferous breccia, 1 and that which 

 Mr. Woodward discovered a ' tough bluish-brown limestone/ 2 that 

 which I found was a yellow sandstone with few vertebrate- 

 remains — a less fossiliferous and thinner Bone-Bed than might 

 have been expected. 3 



Between the outlier on which East Milton is situated and the 

 main mass of Lias near Shepton Mallet, are outliers of Rhaetic and 

 Liassic rocks (1) north of Birrel Farm, (2) between the Horringtons, 

 and (3) at Chilcot, but I have nothing to add to what has already 

 been noted. 4 



In the neighbourhood of Shepton Mallet the principal section is 

 that exposed in the railway-cutting south-west of the town, on the 

 line to Wells. Here the Rhaetic Beds are fairly well developed, 

 but northwards they thin out, passing into conglomerate, and are 

 eventually overlapped by the Lower Lias, which, when it comes 

 to rest upon the Carboniferous Limestone, passes into a massive 

 sparry limestone, locally called * Downside Stone.' 



Near Downside, this Downside Stone rests directly upon the 

 Carboniferous Limestone ; but, a little farther south, near the 

 viaduct, and on the east side of the road, Rhsetic beds have come 

 in between the Lias and the well-planed surface of the steeply- 

 dipping Carboniferous Limestone. This section is the classic one 

 that was pictured by De la Beche 5 ; but in his time, of course, the 

 Rhsetic had not been recognized as a distinct formation, and he 

 called these conglomerate-beds here simply the ' thin gravel base 

 to the Lias.' Charles Moore, however, who was so quick to detect 

 anything Rhsetic, soon discovered that this ' thin gravel base ' 

 contained vertebrate-remains — such as he knew characterized the 

 Rhsetic, so he correlated this conglomerate with that which he 

 had noticed near Hapsford Mills. 6 



This conglomerate at Shepton Mallet is a breccio-conglomerate, 

 consisting of fragments of rocks derived from the Carboniferous 

 Limestone Series (including chert) embedded in a dull-grey matrix 

 in which occur specimens of Pteria contorta, vertebrae of Plesio- 

 saurus, teeth of Saurichthys, Sargodon, Lepidotus, Acrodus, and 

 Gyrolepis, scales of Gyrolepis, coprolites, small quartz-pebbles, and 

 reptilian bones. The same kind of conglomerate is repeatedly met 

 with in digging graves in the Cemetery, and large pieces of bone 

 are sometimes found embedded in it. 



1 Q. J. G. S. vol. xxii (1866) pp. 94-95. 



2 Vert. Sect. Geol. Surv. 1873, Sheet 46, No. 14. 



3 Proc. Geol. Assoc, vol. xxi (1909) p. 225. 



4 'Geology of East Somei-set & the Bristol Coal- Fields ' Mem. Geol. Surv. 

 1876, p. 81. 



5 Mem. Geol. Surv. vol. i (1846) p. 278. 



6 Q. J. G. S. vol. xxiii (1867) p. 507. 



