112 SILURIAN. 



The total thickness of the formation is about 5200 feet. The 

 boundary-line between the Bannisdale Slates and Coniston Grits is 

 very indefinite, owing to the alternation of slaty and gritty beds 

 near the junction. 



In the neighbourhood of Kirkby Lonsdale the beds are thus 

 divided by Prof. Hughes: — 



3. Calcareous beds with RhyiicJwnella navicii/a ( = Aymestry Limestone). 

 2. Dark grey sandstone and shale with Starfishes ( = Lower Ludlow). 

 I. Dark blue flags ( = Upper Wenlock). 



Fossils are scarce : they include Bellerophoti expansus, Pterinea 

 tcmiistriata, Orthonota undata, Rhynchondla navicula, Frotaster, and 

 Phacops Doivningia. 



The lowest beds are seen at several localities in the neighbourhood 

 of Kirkby Lonsdale. Fossils have been found at Tebay Fells, and 

 in the valley of the Lune below Howgill. 



The Bannisdale Slates represent in part the Upper Ireleth Slate 

 Group of Sedgwick, named from Kirkby Ireleth, near Ulverston.^ 



KIRKBY MOOR FLAGS. 



This division is named from Kirkby Moor, near Kendal, in 

 Westmoreland, and is equivalent to the Kendal Group of Sedgwick. 

 It includes grey calcareous flagstones and grits, sometimes in 

 thick beds, locally stained of a reddish colour, of coarse texture, 

 and often exhibiting a massive concretionary structure. It also 

 contains bands of coarse slate and tilestone. The estimated 

 thickness of these beds is 2000 feet. 



The Kirkby Moor Flags are placed on the horizon of the Upper 

 Ludlow series ; they pass downwards into the Bannisdale Slate 

 group. They extend from near Kendal by Benson Knot, through 

 Kirkby Moor to the Lune, but they do not appear to the east of 

 that river. From their occurrence at Hay Fell they are sometimes 

 termed the Hay Fell Flags. Fossils are abundant in some localities. 

 They include Phacops caudatus and P. Dowttifigice, Ceratiocaris 

 inornatiis, Lingula cornea, Orihis orbicularis, O. liinata, Orbicula, 

 Pterinea demissa, Avicula Datibyi, Orthotiottis amygdalinus, Mtirchi- 

 sonia forquata, Orthoceras Kendaletise, etc. The most common and 

 characteristic species are stated by Mr. Aveline to be Holopella 

 gregaria and H. conica. Chonetes lata may also be mentioned. 



The uppermost beds are seen at Helm Hill, near Oxenholme, 

 and consist of hard grey and purple sandstone. The Kirkby 

 Moor Flags are overlaid unconformably by the Old Red Con- 

 glomerate, which belongs to the highest division of the Old 

 Red Sandstone, and really constitutes the base of the Carboni- 

 ferous System. 



1 Q. J. ii. 106. 



