Dawkins—Rhetic Beds. Zoi 
Fig. 24 a, 6. T. Menardi, Lam. <A ventral valve, from the pebble-bed of 
Godalming, 
25. T. Menardi. Dorsal valve, from the Bargate-stone of Guildford. 
26, 27. Terebratulina striata, Wahl. Single valves, from the pebble-bed 
_.. of Godalming. 
(The vertical lines indicate the length of the specimens.) 
Prate XII. 
(All the figures in this Plate are represented of the natural size.) 
Figs. 1 a, b, c,d, & 2 a,b. Terebratula extensa, sp.noy. Specimens from the 
pebble-bed at Tewsley, near Godalming. 
Fig. 3. 7. extensa. A dorsal valve, on which the central, longitudinal 
depression is strongly marked. 
4, T. extensa. Portion of a ventral valve, showing the form of beak 
and its deltidium. 
5 a,b, e,d. T. Boubei (?), D’Archiac. A specimen from Folkestone. 
6. T. Bouber (?). From the Sponge-gravel of Farringdon. 
7 a,b,c. T, Boubei (?). From the pebble-bed at Tewsley, near Godal- 
ming. 
8 a,b,c. T. Tornacensis, D’Archiac, var. Dorsal valve, from the pebble- 
bed near Guildford. 
9. 7. Tornacensis. Ventral valve from Godalming. 
10 a, 6. T. Robertoni (?), D’Archiac. From the pebble-bed at Hurtmore, 
near Godalming. 
ll a,b. T. Robertoni (?). From the pebble-bed near Guildford. 
12 a,b,c. Waldheimia Moutoniana, D’Orb, A specimen from the pebble- 
bed at Shanklin, Isle of Wight. 
13. W. Moutoniana. A specimen from Shanklin, with part of the dor- 
sal valve removed, showing a portion of the elongated loop. 
14 a,b,c. W. Moutoniana. From the pebble-bed of Godalmine. 
15 a,b. Terebratula depressa, Lam. A fine specimen from the Lower 
Greensand of Shanklin, Isle of Wight. 
IJ. OurLine or THE Ruo#TIC FoRMATION IN WEST AND CENTRAL 
Somerset. By W. Boyp Dawkins, B.A. Oxon., F.G.S.; of the 
Geological Survey of Great Britain. 
Contents :—I. Introduction; II. White Lias, or Upper Rheetic; III. Avicula- 
contorta-series, or Middle Rheetic; IV. Lower Rheetic (Marls). 
I. HE identification of the Rhetic Formation in Britain, pre- 
viously discovered to be intercalated between the Keuper 
Marls and Lower Lias Shales in Germany, we owe to the labours of 
Dr. Wright, F.G.S., and Mr. Charles Moore, F.G.S., In the year 
1860, the former published an account of the strata beneath the 
Lias, characterized by the occurrence of Avicula contorta; the latter, 
in the following year, showing in a most valuable paper the true rela- 
tion of the sandstones, shales, and limestones to the White Lias above 
and the Keuper below, added upwards of twenty-eight new species 
to the list of British Fossils. ‘The White Lias, which Dr. Wright 
incorporated with the group of beds characterized by Ammonites 
planorbis, Mr. Moore considered to belong to, and to constitute an 
upper member of, the Rhetic Formation. Lastly, in 1861, after a 
