Conus in the Lias of Normandy, 295 



Since my return from Caen I have seenM.AlcideD'Orbigny, 

 who has also visited lately the quarries of Fontaine-Etoupe- 

 four. A consideration of the numerous fossils obtained by 

 him from the rock in which the Cones occur leads him to 

 the opinion that the breccia filling the rents is of the age 

 of the upper lias. Among other liassic species he pointed 

 out to me the Pentacrinus cingulatus. These and other 

 well-known species were accompanied by many others new to 

 the oolite, of the genera Nucula, Area, Delphinula, Trochus, 

 Cirrus, and several more, for which new genera must be 

 established. 



It may be objected that the mineral character and colour 

 both of the breccia filling the rent and of the overlying beds 

 differ totally from those of ordinary lias, for the rock is a pale 

 brown ferruginous limestone. But Mr. Lonsdale informs me 

 that near Radstock the great deposit of blue lias is repre- 

 sented by only a few feet of a pale brown granular rock, so 

 like inferior oolite that the quarry men apply the same name 

 to it. But this gritty lias is clearly not inferior oolite, being 

 separated from that rock by blue clay from 100 to 200 feet 

 thick. (See Lonsdale, Geol. Trans., vol. iii. 2nd series, p. 245.) 

 The " corn-grit" above-mentioned is a granular light brown 

 limestone, but of a closer and finer grain than the gritty lias. 

 Yet Radstock is only seven miles S.W. from Bath, where the 

 lias is well-developed, with its usual characters. 



In proceeding from Caen to Fontaine-Etoupe-four the ge- 

 ologist obtains no sections which display the superposition of 

 the different members of the oolitic series, but he finds the 

 white oolite of Caen give place to the ferruginous oolite of 

 Eterville, which resembles in appearance the oolite of Dundry. 

 Travelling still further south he meets with the beds of Fon- 

 taine-Etoupe-four already described. As all these formations 

 appear to be everywhere horizontal, and the surface of the 

 country, following the direction above-described, is constantly 

 attaining a higher level, we might naturally have expected to 

 reach newer instead of older beds. But it must be remem- 

 bered, that a slight dip, and one quite inappreciable in the 

 space of a quarry, as for example, an angle of five degrees, 

 might in a distance of six miles cause a difference of level of 

 more than 800 feet, so as to allow beds which may be con- 

 cealed beneath the oolite building-stone at Caen to crop out 

 in a high platform at Fontaine-Etoupe-four. 



Having offered these remarks on the position and age of 

 the containing rock, I shall now describe the Cones themselves, 

 in which task I have had the assistance of Mr. George Sow- 

 erby, who examined the original specimens at my request 

 during a late visit to Normandy. 



