138 THE LIAS AMMONITES. 



of Gloucester, Somerset, Dorset, and at Blue Wick, or Blea-Wyke, near Robin Hood's 

 Bay, on the Yorkshire coast. It may be most advantageously studied in the fine section 

 at Frocester Hill, and in other smaller exposures in the Nailsworth and Brimscombe 

 Valleys in Gloucestershire. The following section of Frocester Hill, near Stonehouse, 

 affords one of the best types of the zone of Lytoceras Jurense in the county of Gloucester. 



Fig. 8. — Section of Frocester Hill, near Stonehouse. 



Harpoceras Murchisonm. 

 Harpoceras opalinum. 



Lytoceras jurense. 



Harpoceras bifrons. 



Harpoceras serpentinum. 



^s_i*.. Amaltheus margaritatus. 



I 



a, b, c. Inferior Oolite ; 70 feet. Zone of Harpoceras Murchisonce. 



C Zones of Harpoceras opali- 

 D, E. Calcareo-ferruffinous sandstone (Cephalopoda bed) ; 6 feet, j j r ^ 



^ \ r r / ■ (^ jjjj^ 2„ij Lytoceras jurense. 



F. Grey, yellow, and brown sands, with inconstant, concretionary bands of calcareous sand- 



stone; 150 feet? Zone oi Harpoceras bifrons. 



G. Upper Lias shale ; 80 feet. Zone of Harpoceras serpentinum. 



H. Marlstone ; hard calcareous sandstone, resting on brown and grey sands, with bands and 

 nodules of ferruginous sandstone ; 150 feet. Zone of Amatlheus margaritatus. 

 I. Middle Lias shale. Zone of Aegoceras Henleyi. 



In very few localities, where the sands are exposed along the escarpments of the 

 Cotteswolds or in the beautiful valleys intersecting these hills, are they found to contain 

 organic remains ; but fossiliferous seams have, however, been discovered at Frocester, 

 Brimscombe, Nailsworth, Uley Bury, North Nibley, and Ozleworth, and doubtless will 

 be detected in other localities in this neighbourhood when the strata are exposed. 



The fossiliferous bed at Nailsworth lies near the base of the sands 4 or 5 feet above 

 the Upper Lias clay, and consists of a fine soft ferruginous marly sandstone, of a rich 

 brown colour, containing much peroxide of iron, with many shells, mostly of the same 

 species found in the Cephalopoda-bed at Frocester. The difference between these 

 two beds is inaportant, and deserves to be noted, as the Cephalopoda-bed at Frocester 

 overlies the sands, whilst the fossiliferous bed at Nailsworth underlies them near their 

 base, clearly proving that the sands and Cephalopoda-bed form one stage. 



In Somersetshire the Jurense-mn& is met with in several sections south of the 

 Mendips, resting upon the Crmiia-chys of the Upper Lias, as in the section at Straw- 



