Vol. 60.] RHJETIC OF THE S JUIII-WALES DIRECT LINE. 107 



The thickness of the R hectic Series here is practically identical 

 with that at Stoke Gifford, and the correspondence between the 

 Upper Beds at the two localities is very close. The two sections 

 agree, too, in the absence of the Bone-Bed. 



East of Lilliput Bridge a splendid Rhaetic section comes on, and 

 extends as far as a point to the east of the Old-Red-Sandstone out- 

 crop lying west of Chippiug-Sodbury railway-station. The series 

 varies a good deal in thickness, being thickest where the Palaeozoic 

 rocks have been much denuded. At two points where large 

 rounded hummocks of the Palaeozoic project into the Rhaetic, the 

 Black Shale is deposited on them in an arched manner, forming an 

 anticline of bedding. The section is remarkable for the occurrence 

 of a very rich Bon e-B e d at the base, but this is not uniformly distri- 

 buted. It is first met with as one passes east from Lilliput Bridge 

 at a point about 150 yards from the bridge : it extends for a distance 

 of about 130 yards, and then again disappears, reappearing after 

 <omc 20' > yards, and extending continuously to the end of the 

 Paheozoic outcrop. 



The Upper Rhaetic agrees more closely with that of Stoke 

 Gittord. and shows less lateral variability than the Lower. A 

 point 1U0 yards to the east of the bridge for the road from Kin- 

 grove Farm (see fig. 2, p. 198) gave the following section: — 



Cotiiam Marble. Thickness infect inches. 



Grey shale, containing plant-beds at 15 and at 

 18 inches from the top. Darwinula and 



Estheria 2 'J 



Brown unfossiliferous shale 1 



^ •{ Argillaceous limestone G 



I Brown or grey shale, with lenticular beds and eon- 



IV. ■{ cretions of argillaceous limestone at two or three 



levels. Fragmentary shells, Cardinal cloacinn?/i 



etc , ;> 



Black shales, with dark calcareous bands : Pecten ~] 

 valoniensis, Cardinm rha-ticum, and C. c/oacinum 

 are very abundant, Achilla contort a rare. 

 f Black shales, with thin sandy layers : Avicula con- 

 torta and Schizodus Ewaldi are very abundant ; 

 j j ! Card in m cioacinum and Myophoria post era, )■ 



} plentiful : Modioli/ sodburiensis teems in the 

 sandy layers : Pecten valoniensis is apparently 

 | j ^ absent. 



3 ' ( Non-fissile black shale, with a rare tooth or vertebra. 



"^ I Soft black clay, crowded with vertebrates J 



I. ■{ Hard Bone-Bed, containing quartz-pebbles and 

 crowded with vertebrates; Plicatula cloacina 

 \ y is not infrequent 3 



The foregoing constitutes a typical section of the Sodbury Rhoetic : 

 but the beds show considerable lateral variability, lenticular hard 

 bands sometimes of a gritty nature, though generally of limestone, 

 appearing at various levels in the Black-Shale Series. 



