LOWER LIAS. 



19 



Gtyphcea obliquata. M. C. t. 112. 

 Hippopodium ponder -osum. M. C. t. 250. 

 Lima antiquata. M. C. t. 214. 

 Pecten. Three undescribed species. 

 Pentacrinites scalaris. Goldfuss. 

 Serpula. 



Vertebra of the Ichthyosaurus have also been 



Spirifer. 



Turrit ella muricata? M. C. t. 499. 

 Unio ? 



found. 



The Ammonite which I have named after the town of Cheltenham A. Cheltiensis, is 

 found also in the Lias of Lyme Regis in Dorset. It is represented in the following wood- 

 cut (a.), together with the two most characteristic bivalve shells, Gryphcea incurva (5.) 

 and G. obliquata (c). 



The cement stones frequently contain Belemnites, and Ammonites Cheltiensis, occa- 

 sionally covered with an iridescent nacre. Many of the layers of this shale are highly 

 charged with iron pyrites (sulphuret of iron) , and when the fossil remains are coated 

 with this mineral, it generally gives to their surface that bright metallic lustre seen 

 upon many of the Ammonites. 



Limestone of the Lower Lias Shale, (g. of section.) The right bank of the Severn 

 in the environs of Gloucester is occupied by several plateaus of Lias, which in some 

 points of their escarpment, as at the western part of Highnam Court, present good 

 sections of the passage of the lowest beds of the formation into the marls of the New 

 Red Sandstone. These consist of laminated shale, containing a few thin beds of 

 calcareous flagstone, the whole dipping to the east and south. In following the Lower 

 Lias thence through Gloucestershire and Worcestershire, its line of junction with the 

 marls of the New Red Sandstone is not confined to the left bank of the Severn as 

 marked upon previous geological maps 1 . The Lower Lias also occupies the hills 

 between Deerhurst and Tewkesbury, and appearing on the right bank of the Severn, 

 is quarried at Forthampton Court and at Bushley, Worcestershire ; and still farther 

 to the north it appears in the insulated hill of Longdon Heath near Upton. This is 

 the last outlier on the right bank of the river, the formation thenceforth following 



1 For new outline west of Gloucester by Corsewood Hill, to Combe Hill on the left bank of the river, see the 

 Map annexed to this work. 



a 



2, 



