122 LIAS^ OF ENGLAND AND WALES: 
remarked that these beds (which belong to the zone of Ammonites 
planorbis) were known to the quarrymen as " sarpent-stone."* 
At the Tredegar quarry we find limetones and clays similar to 
the beds at Lliswerry, but on a somewhat higher horizon. They 
yield Ostrea liassica and Lima, but the best cement-beds lie below 
the layers that were exposed at the time of my visit in 1888. 
The total thickness of stone-beds is about 40 feet, according to the 
lime-burner. 
At Gold Cliff, south east of Newport, we find the lowest beds 
of the Lias, comprising 10 or 12 feet of dark shales and grey 
argillaceous limestones, resting on the Rheetic Beds. I obtained 
Ammonites planorbis, Cardinia, Gryphwa arcuata, Modiola 
minima, Ostrea liassica, and Pholadomya. The name Gold Cliff 
was derived from the glittering appearance of the iron-pyrites 
thai was formerly to be seen in the black (Rhretic) shales.f The 
greater portion of the cliff is now walled-up for the protection of 
the coast. 
In the Severn Cliff, east of Chepstow, and north of Beachley, 
the lowest beds of the Lower Lias (zone of A. planorbis') are 
present above the Rhaetic Beds. Ammonites planorbis, A. Johnstoni, 
Ostrea liassica, and Lima aiaantea have been recorded. J 
* Note-Book of an Amateur Geologist, 1881, p. 34. 
j" Buckland and Conybeare, Tram. Geol. Soc., ser. 2, vol. i. p. 305. 
j Proc. Cotteswold Club, vol. vi. p. 271. 
