Geological Society. 61 



Maclauchlan is of opinion that this difference may have been pro- 

 duced by the masses of trap which are associated with the slates. 



The conglomerate sandstone of Dinas Head, which occurs also in 

 Newport Bay and at Trewyddel, near Cardigan, is stated to resem- 

 ble one of the conglomerates of the Caradoc sandstone described by 

 Mr. Murchison ; and the crinoidal stems which it contains, to agree 

 with analogous remains found by Mr. Murchison in the Caradoc 

 sandstone at Little London, May Hill*. 



In addition to the phsenomena which occur in the immediate vi- 

 cinity of the section, Mr. Maclauchlan alludes to indications of anti- 

 clinal lines near Narberth and at Camrose, in Southern Pembroke- 

 shire ; also at Solfach, south-east of St. David's, and at Porthllisky, 

 to the south-west of that city. At the latter village the dip changes 

 to the westward, and continuing to alter, assumes in Whitesand Bay 

 a northwardly direction. This dip also prevails at St. Laurence, 

 thirteen miles east of St. David's Head ; at Leweston, three miles 

 south of St. Laurence, and at Long Ford, about two and a half miles 

 south of Llandysilio. Trappean ash also is stated to occur near green- 

 stone at Penbury (Penberry, Ord. Map) Hill, two and a half miles 

 north-north-east of St. David's ; at Llanllawer, two miles south-east 

 of Fishguard ; and at Carningley, one mile south of Newport. 



Though the summit of the principal Pembrokeshire chain is 

 roofing-slate, yet trap-rocks occur near the top, and are described by 

 the author as continuous through the district, extending to Plumb- 

 stone Mountain (five miles north-west of Haverfordwest) and to St. 

 David's Head, re-appearing at the Bishop and Clerks and the Hat 

 and Barrels rocks, and at the Smalls light-house. At Fishguard and 

 Strumble Head, three miles west of Fishguard Bay, the trap is co- 

 lumnar. On the north-east of the chain at Whitechurch (Eglwys- 

 wen), six miles south-east from Newport, on the east at Llanfirnach 

 (Llanfrynach, Ord. Map), and on the south at Llanglwydwen, are 

 beds of dark carbonaceous shale, which have been fruitlessly worked 

 for culm ; they appear to mantle round the trap, but preserve a 

 northerly dip ; they are accompanied by lead-veins, one of wliich, at 

 Llanfernach, has been worked successfully. At Llanglwydwen Bridge 

 are indications of copper in a lode in contact with a considerable 

 bed of limestone. Mineral veins also exist along the coast, from 

 Newgate, in St. Bride's Bay, to St. David's Head. 



" IJescription of some remains of a gigantic Crocodilian Sau- 

 rian, probably marine, from the Lower Greensand at Hythe ; and of 

 Teeth from tlie same formation at Maidstone, referable to the genus 

 Polyptychodon," by Richard Owen, Esq., F.G.S. 



The fossil saurian remains from the lower greensand discovered 

 by Mr. H. B. Mackeson include portions of the iliac, ischial and 

 pubic bones, a large proportion of the shaft of a femur, parts of a 

 tibia and fibula, and several metatarsal bones. In consequence of 

 the absence of vertebrae and teeth, tlie determination of the specific 

 characters of this Saurian is, the author states, a subject of great 



» Silur. Syst., pi. xx. fig. 19. 



