390 MR. L. KICHABDSON ON THE RBL&TIC [Aug. I903, 



31. The Rh^tic and Lowek Lias of Sedbttey Cliff, near Chep- 

 stow (Monmouthshire). By Linsdall Richardson, Esq., F.G.S. 

 (Read June 24th, 1903.) 



[Plate XXIV — Vertical, Section.] 



On the opposite side of the Severn to Aust Cliff, and 2 miles north- 

 north-west of that section, there is a corresponding elevation known 

 as Beachley, Aunard's, or Sedbury Cliff. Chepstow lies to the west- 

 north-west, and in a direct line is distant about 1\ miles, but by 

 road about 2^ miles. 1 have distinguished the cliff-section as that 

 of Sedbury, since Sedbury Park, the country-seat of Sir William 

 Marling, Bart. — to whom, and to Mr. S. S. Marling, I am indebted 

 for permission to examine the cliff and for kind assistance — is 

 situated on the Rhaetic and Liassic outlier. 



The literature relating to the section is not voluminous. In that 

 which has come under my notice I find it incidentally mentioned 

 in several papers, 1 and briefly noticed in two other communications. 

 The earliest account is that given by the Rev. P. B. Brodie, but it 

 is based upon information supplied by Mr. Higgins. 2 This account 

 may be summarized as follows. There is a development of true 

 ' Insect-Limestone ' above the ' Landscape-Stone,' and although they 

 are separated one from the other by 4 feet of shale at the eastern 

 end of the section, at the western they thin out and blend as at 

 Aust. The ' Landscape-Stone ' contains a great variety of insect- 

 remains, some of which are tolerably perfect. The ' Cypris- and 

 Plant-Bed' is seen in its proper position, and in every case possesses 

 a true ' Landscape ' character. Sir W. V. Guise observed that this 

 section closely resembled the exposure at Aust, yet presented 

 differences which gave it a certain speciality : — 



' The exposure of Lower Lias is considerably greater, and abounds in such 

 characteristic fossils of the formation as Lima gig 'ant ea, Ammonites pianorbis, 

 and its thicker variety A. Johnstoni, Ostrea liassica, etc. The Rhaetic Beds 

 resemble very closely those at Aust — the "Bone-Bed" is but feebly repre- 

 sented — Avicula contorta is present occasionally.' 3 



It will be seen, then, that very little is known concerning 

 the sequence of the component beds of the Rhaetic Series at this 

 locality : hence the origin of the present paper. Unfortunately the 

 cliff is very awkward to examine, and even when an apparently- 

 suitable place for the investigation of the Rhaetic Beds has been 

 discovered, these deposits are found to be hidden under a con- 

 siderable accumulation of slipped rock. The dip being riverwards, 



1 H. Wills, Trans. Clifton Coll. Sci. Soc. pt. iii (1872) pp. 49,. 55 ; Brit. Assoc. 

 (Bristol, 1898) Handbook of Excursions, ' Aust & Over Court' ; S. S. Buckman, 

 Proc. Cotteswold Nat. F. C. vol. xiii (1901) p. 278. 



2 ' A History of the Fossil Insects in the Secondary Rocks of England ' 

 1845, pp. 83-85. 



3 Proc. Cotteswold Nat. F. C. vol. vi (1877) pp. 270-71. 



