CLASSIFICATION OF THE 



SEDGWICK. MURCHISON, 1868. JUKKS, 1863. 
Ledbury Shales. Passage Beds. 
r Downton Sandstone, Bone Bed, and f Tilestones, and | 
Upper Ludlow. Upper Ludlow. : 
Zz 
x Aymestry Limestone, and S Aymestry Limestone. S 
= TS Sp Ff Tel = 
4 Lower Ludlow. tae 3 4 Lower .Ludlow. B 
4 NM p} 
oD Wenlock Group. # | Wenlock Limestone and Shale. a 
a > 
Lower Wenlock Group. 5 | Woolhope Limestone and Shale. P 
i May Hill Group. L Upper Llandovery. 
Zz 
= 
[ : Upper Bala Group. 5 Lower Llandovery. ¥ 
| = { Middle Bala Group. “ 4 Caradoc and Bala Rocks. 2 
i=) ace 
Lower Bala Group. = | Upper and Lower Llandeilo Rocks. ag 
Arenig or Skiddaw Group. aa 8 g 
Zz = 
S 4 ( Tremadoc Group. < 
Eye! 
a =| Ffestiniog Group. Lingula Flags, or =e 
Menevian Group. PRIMORDIAL SILURIAN. 
Harlech Group. 1 : 
z 
a ¢ Longmynd, Bangor, and | CAMBRIAN, = 
= gmyr 5 > a) 
L 4 | Lianberis Group. | a 
‘f 'S) 
In a Table of Strata prepared by Mr H. W, Bristow (1872), 
R. I. Murchison as forming an intermediate or Middle Silurian, 
Tremadoc, Lingula and Meneyian beds forming the Lower Silurian. The Graptolite shales being equal to the Arenig or Stiper- 
stones. In the Lake district the Kirby Moor flags are equivalent to the Tilestones and Upper Ludlow, and the Bannisdale beds 
represent the Aymestry limestone, Lower Ludlow, Wenlock and Woolhope series. The Coniston Grits and Flags are equal to the 
Denbighshire Flags and Grits. The Stockdale slates (Graptolite mudstones) being equal to the Tarannon shales. 
The Coniston lime- 
stone is equivalent to the Caradoc or Bala beds. The Green slates and Porphyry are equivalent to the Upper Llandeilo, and the 
Skiddaw slates to the Arenig beds or Lower Llandeilo. 
the Upper and Lower Llandovery beds, considered by Sir 
are kept distinct. The Lower Llandovery, Caradoc, Llandeilo, 
) 
