JTTRASSTC OF THE TAEIS BASIX. 



545 



by fossils which have decayed, leaving their exteriors perfectly 

 moulded. The most abundant fossils are some large curved Montli- 

 valtice (M.subnigra, d'Orb.*?), various peculiar Nerincece, small Cerithia, 

 My til us pectinatus, Trigonia acide'ata, d'Orb., T. TombecJci? (T. Me- 

 riani of d'Orbigny, but not that species), and Astarte bicostata. 

 Thus the common fossils are tbe peculiar ones, and one must fall 

 back upon more detailed lists of rarer fossils. Amongst those 

 quoted by d'Orbigny, the most important for correlation are Belem- 

 nites Royeri (probably from the lower portion), Ammonites achilles, 

 Katica grandis, N.hemisplicerica, Turbo princeps, Cardium corallinum, 

 Mytilus acinaces, Lima Iceviuscida, Avicula polyodon, Pecten subarti- 

 culatus, Terebratvla insignis, and Hemicidaris crenularis. None of 

 the others having a contrary tendency, it is plain that in the great 

 mass composing this series we have represented the shell-limestone 

 usually included in the Corallian, up to and including the Coral Rag 

 itself; though Cidaris florigemma does not appear to nourish here, 

 and the corals are not Astrsean. Passing south towards higher beds, 

 we find some more marly limestones with Plioladomya Protei and 

 Pinna obliquata not uncommon. If the latter shell may be trusted 

 to keep to a single horizon, it should represent the lithographic 

 limestones overlying the chalky limestones of Bourges. However, 

 at the next point, Point du Che, a fine development of a Coral Rag- 

 is seen. This is credited with more than 200 feet by Planes ; but 

 as the next series named is the Yirgulian marls, it is obvious that 

 the Astartian beds are included in this. The cliffs have a height 

 of 30 feet to 40 feet ; and all is apparently Coral Rag, though on a 

 higher horizon than usual. Fossils like Area tetragona, Lima verdu- 

 nensis, Terebratida, are abundant, with spines of Cidaris ; to which 

 may be added from d'Orbigny's list Nautilus giganteus, Xerince.a 

 Mandelslohi, Pinnigena Saussurei, Diceras arietinum, and Hhyncho- 

 nella pinguis (" inconstans "). 



This portion of the series may therefore fairly be placed on the 

 horizon of the Diceras- or Supracoralline beds, like the far-off coral- 

 liferous deposits at Xovion ; and it corresponds with the uppermost 

 portion of the Corallian of the Charente, as described by Coquand. 

 At the cliff near Angoulins, very little to the south of the Point du 

 Che, the last of the rubbly limestones, with Lima Iceviuscida and 

 Ostrea cf. gregaria, is seen occupying the base, overlain by about 

 5 feet of marly beds with Plioladomya Protei and Ceromya ecccen- 

 trica of large size, and then a hard limestone band with many fossils, 

 amongst which are corals, Pecten striatus, and Cidaris Smithii?, 

 but also a great abundance of Terebratida Leymerii. The presence 

 of this last species would indicate Astartian beds, which are other- 

 wise unrecognized ; and these are doubtless the beds to which Co- 

 quand alludes when he says d'Orbigny has placed them with the 

 Corallian on account of their being calcareous. As noted, however, 

 by Hebert (54) only nine of the species found here are common to 

 the Corallian beds at the Point des Minimes. In the same paper we 

 learn that the marls of Chatelaillon, which show the upper succes- 



Q. J. G. S. No. 148. 2 o 



