5-iO PEOCEEDTXQS OF THE GEOLOGICAL SOCIETY. [June 17, 



a breadth of nearly one line in the fully developed portion. Axis 

 slender. Common canal narrow. Cellules from yV ^^ 8 ^^ ^^ 

 inch in length, inclined to the axis at an angle of fi^om 25° to 30°, 

 narrow, in contact for about two-thirds of their entire length ; 

 from 20 to 25 in the space of an inch ; the cell-mouths making 

 more than a right angle with the general direction of the cellules, 

 and forming, therefore, a very obtuse angle with the axis. Base 

 slender and curved, somewhat resembling that of G. Sagittarius, Linn. 



This very distinct species is readily recognized by the obliquity 

 of the long and narrow cellules, and by the open angle which the 

 cell-mouth makes with the cell-walls. The specimens which I have 

 discovered from the base of the Coniston Plags are exquisitely pre- 

 served in relief, and are the first examples of the species which have 

 hitherto been found in Great Britain. 



Loc. Coniston Hags of Skelgill, near Ambleside. 



Grapiolites peiodox, Bronn. PI. XX. figs. 6-8. 



G. ^-riodon, Barrande, Grapt. de Boheme, pi. 1. figs. 1-14. 

 G.priodon, Geinitz, Graptolithen, pi. 3. figs. 20-27, 29-32, 34. 

 G. Ludeasis, lEurch. Sil. Syst. pi. '2Q. figs. 1, 1 a. 



Stipe simple, monoprionidian, commencing proximalLy in a slen- 

 der, straight or curved base, and then proceeding in a straight 

 or slightly curved Hne. Axis cylindrical. Common canal well 

 marked. Cellules in contact near the base for the inner half 

 or thereabouts, and then gradually diverging from one another 

 owing to the diminution of their calibre, forming an angle of about 

 45° with the axis, cylindrical, tapering gTadually from base to apex, 

 and varying from 22 in the adult to 30 in the younger specimens in 

 the space of an inch. The most characteristic point, however, about 

 the cellules is the peculiar double curve which they describe, the 

 inner third being rectangular to the axis, the middle third bent up- 

 wards, and the outer third again curved downwards, so that the 

 cell-mouth finally comes to look more or less completely downwards 

 or outwards. 



G, priodon, though often confounded with G. colonus, Barr., is 

 readily distinguished from any other species known to me. G. 

 colonus is easily separated by the shape of the frond and by the 

 facts that the cellules are in contact throughout almost their entire 

 length, that they do not taper gradually from base to apex, and that 

 they want the peculiar double curvature so , characteristic of the 

 cellules of G. jpriodon. 



G. priodon is not only found in the Coniston Grits and the higher 

 beds of the Coniston Flags, but occurs likewise in the mudstones at 

 the base of the latter, serving, therefore, to show the indivisibility 

 of the entii^e series. 



Loc. Coniston Flags of Broughton Moor and Skelgill Beck ; Conis- 

 ton Grits of Hebblethwaite GiU, near Sedbergh. 



Grapiolites coLOxrs, Barrande. PI. XX. figs. 9-11. 



There occur in the Ludlow rocks in the neighbourhood of Ludlow, 



