Vol. 59.] AND LOWER LIAS OF SEDBURY CLIFF. 391 



slips on a large scale are of frequent occurrence ; and the work of* 

 destruction is hastened by a number of springs, which have also 

 caused large deposits of travertine to be formed, and masses of this 

 are seen on the beach. 



The chief portion of the cliff-section now to be described has a 

 direction north-east and south-west ; the dip of the beds is south- 

 south-easterly, at an angle which does not exceed 3°. 



The Upper Keuper Marls constitute the base of the section, 

 and are exposed for a thickness of about 66^ feet. This thickness 

 includes 56 feet of red marl, and 10-J- feet of ' Tea-green Marls.' 

 The term ' Tea-green Marls ' for these 10£ feet of deposit is quite 

 a misnomer here, for the predominating tint is yellow. They 

 may be thus described : — 



Thickness in 

 Feet inches. 



(a) Yellowish-green, somewhat soft marl 2 



(b) Hard band of marlstone 7 to 11 



(c) Marl similar to a, but with hard nodular 

 7 6 



The 'Tea-green Marls/ together with the greater number of 

 the component deposits of the Lower Rhsetic stage, are best examined 

 at the step-fault shown in the accompanying figure (p. 392), and 

 distant about 30 yards north-east from the place where Offa's Dyke 

 terminates on the cliff. 



Resting upon the ' Tea-green Marls ' is the Bone-Bed, but here 

 (as the late Edward Wilson showed was also the case at Pylle Hill, 

 Bristol) the line of junction between the two stages — the Upper 

 Keuper and Lower Rhaetic — is sharply defined, palseontologically and 

 lithologically. On the other hand, however, the ' Tea-green Marls ' 

 graduate downward imperceptibly into the Red Marls. The Bone- 

 Bed usually occurs in the form of one or more layers of light-grey, 

 micaceous sandstone ; but this development is sometimes replaced 

 by an interesting conglomerate, in all respects similar to that so 

 well known at Aust Cliff. The latter occurrence, however, is the 

 exception rather than the rule. One subangular mass of marl had 

 a diameter of 8 inches. In the conglomerate vertebrate remains 

 are well-preserved, but often crumble away when an attempt is made 

 at extraction. No less than fifteen specimens of Sargodon tomicus 

 were observed in a piece of the Bone-Bed with a superficial extent 

 of one square inch, but unfortunately shivered while the piece was 

 being detached from the larger mass. To Dr. A. Smith Woodward, 

 F.R.S., I am indebted for kindly examining a few of the fish- 

 remains ; but it will be noticed that in the list of organic remains 

 from Bed 15 appended to PL XXIV x no mention is made of the 



1 In order to facilitate the correlation of this section with those in North- 

 West Gloucestershire, I have employed numbers for the various beds corre- 

 sponding with those given in my paper on ' The Rhsetic Bocks of North- West 

 Gloucestershire ' Proc. Ootteswold Nat. F. C. vol. xiv (1903) pp. 127-74. 



