SILURIAN OF THE LAKE-DISTRICT. 875 



Fossils of the Ashgill Shales. 



ACTINOZOA. 



Petraia subduplicata, var. crenulata. Near Dent. 



ECHINODERMATA. 



Glyptocrinus Troutbeck. 



Echinospbaerites Asbgill. 



Annelida. 



Oornulites Nanny Lane, Troutbeck, 



Crustacea. 



Phyllopods Spengill; Skelgill. 



Spines of do Spengill. 



Trinucleus concentricus Helm Grill &c. 



Ogygia? Scot Beck, Windermere. 



Phacops apiculatus, Salt Rother Bridge ; Nanny Lane ; Skelgill ; 



Ashgill. 



Phacops mucronatus, Brongn, var. . . . Nanny Lane ; Skelgill ; Asbgill. 



Phacops, sp. (not obtusicaudatus) . . . Sarly Beck, near Dent. 



Pbacops (sp. with long bead-spines) . . . Scot Beck. 



Calymene , Asbgill. 



Mollusca. 



Lingula Skelgill ; Asbgill. 



Ebyncbonella Rebecca Hill. 



Ortbis biforata, Schloth Near Dent ; Skelgill; Asbgill. 



O. protensa, Sow Skelgill ; Asbgill ; Eebecca Hill. 



O. vespertilio, Sow Near Dent ; Skelgill ; Asbgill. 



O. calligramma, Balm Near Dent. 



Stropbomena siluriana, Dav Fairy Gill; Spengill; Appletbwaite 



Common ; Nanny Lane ; Skelgill ; 



Asbgill ; Rebecca Hill. 



S. depressa, Balm Near Dent. 



S. alternata Near Dent. 



S. (sp. with fine striae) Skelgill ; Asbgill. 



Belleropbon trilobatus ? Ashgill. 



On comparing this list with that of the Coniston-Limestone fossils, 

 it will be seen that only a few species are common to the two for- 

 mations, and those are the very common Bala fossils, such as Orthis 

 vespertilio ; whilst the typical Ashgill-shale fossils, viz., Phacops 

 mucronatus, var., Phacops apiculatus, Orthis protensa, and Stropho- 

 rnena siluriana, have not, to my knowledge, been yet found in the 

 Coniston Limestone. The palaeontological evidence, then, fully bears 

 out the conclusion arrived at from lithological character and strati- 

 graphical relations, that the Ashgill Shales should be viewed as a 

 group distinct from the Coniston Limestone. 



The fossils are all of Bala type, though some, as Oornulites and 

 Strophomena siluriana, point to a rather higher horizon, and they 

 bear out the conclusion of Salter (Cat. Cambr. & Sil. Poss. of Woodw. 

 Mus. p. 72) that these beds are referable to the Upper Bala. 



Another point of great interest in this series is its great irre- 

 gularity of thickness, due either to unconformability or to overlap of 

 the overlying series. It is impossible, in the present state of our 



