554 



AYMESTRT LIMESTONE. 



Fig. 624. 



[Oh. XXVIL 



Fig. 625. 



Peniamerus Knightii, Sow. Aymestry. £ nat. size. 

 a.' View of both valves united. 



o. Longitudinal section through both valves, showing the cen- 

 tral plates or septa. 



IAngula Zewisii, 



J. Sow. 

 Abberley Hills. 



a white limestone of Upper Silurian age, on the banks of the Is, on 

 the eastern flank of the Urals in Kussia, and a similar species is fre- 

 quent in Sweden. ' 



Three other abundant shells in the Aymestry limestone are, 1st, 

 Lingula Lewisii (fig. 625); 2d, Rhynchonella Wilsoni, Sow. (fig. 626), 



Fig. 626. 



Rhynchonella (Terebralula) Wilsoni. Sow. Aymestry. 



which is also common to the Lower Ludlow and Wenlock limestone ; 

 3d, Atrypa reticularis, Linn. (fig. 627), which has a very wide range, 

 being found in every part of the Upper Silurian system, and as far 

 down as the Lower Llandovery rocks. 



Fig. 62T. 



Fig. 628. 



Atrypa reticularis, Linn. (Terebraiula affinis, Min. Con.) Phragmoceras ventricosum, 

 Aymestry. J. Sow. 



a. Upper valve. o. Lower valve. (Orthoceras ventricosum, Stein.) 



c. Anterior margin of the valves. Aymestry; a nat. size. 



The Aymestry Limestone contains so many shells, corals, and trilo- 



