A. J. Jukes- Br otme — -On Rock- Classification. 297 



Systems. 



ICENIAN. 



HANTONIAN. <^ 



CEETACEOUS. <( 



JUEASSIC. 



TEIASSIC. 



CARBON- 

 IFEROUS. 



DEVONIAjST. 



SILURIAN. 



ORDOVICIAN. 



CUMBRIAN. 



Primaky Divisions. 



Pleistocene. 



Pliocene. 

 Miocene. 



Oligocenb. 



Eocene. 



Upper, 



Lower. 

 Upper. 



Middle. 



Lower. 



Ketjper. 



muschelkalk. 



BUNTER. 



Dyas. 

 Upper. 



Lower. 



Upper. 



Middle. 

 Lower. 



Clunian. 

 Salopian. 

 Valentian, 



Bala Rocks. 



Llandeilo Flags 

 Arenig Grits. 



Upper. 

 Lower. 



Groups or Stages. 



^ Recent deposits. Raised beaches and 

 ( Valley gravels. Glacial deposits. 

 \f Forest Bed, Norwich Crag, Red Crag, 

 ( and White Crag. 



None in Britain. 

 ( Upper (wanting in Britain). 

 \ Hempstead and Berabridge Beds. 

 I Lower Tleadon Beds. 

 ^ Bagshot and Barton beds. London 

 ( Clay. Lower London Tertiaries. 

 ( Upper. 

 Chalk Middle. 

 ( Lower. 

 Upper Greensand and Gault. 

 Vectian or Lower Greensand. 

 "Wealden and Neocomian. 

 Purbeck and Portland beds. 

 Kimmeridge Clay. 

 Corallian and Oxford Clay. 

 Great Oolite series. 

 Inferior Oolite series. 

 Upper Lias. Marlstone and Sands. 



Lower Lias and Rhaetic ? 

 Marls, Sandstones, and Conglomerate. 

 Absent in Britain. 

 U. Sandstone. Pebble Beds. L. 



Sandstone. 

 Magnesian Limestone and St. Bees 



Sandstone. 

 Marl Slates and Penrith Sandstone. 



I Upper. 

 Coal-measures | Middle. 

 ( Lower. 

 Millstone Grit. 

 Carboniferous Limestone Series or 



Bernician. 

 Tuedian and Upper R.S. 

 Barnstaple, Marwood and Pickwell 



Down Beds. 

 Mortehoe Slates and Ilfracombe Beds. 

 Hangman Grits and Lynton Beds. 

 TUestones and DoAvntou Sandstone. 

 U. Ludlow and Aymestry Limestone. 

 Lower Ludlow. Wenlock Limestone, 



shale, and "Woolhope Limestone. 

 Tarannon Shales. May Hill Sand- 

 stone. Lower Llandovery. 

 Hirnant Beds. Ashgill Shales, Bala 

 and Coniston Limestones, Slates and 

 Sandstones. 

 Flags with 0. Buchii. Shales with 



As. tyrannus. Llanvirn series. 

 Upper and Lower grits. 

 Tremadoc slates. 



( Dolgelly group. 

 Lingula Hags | Ffestiniog group. 

 ( Maentwrog group. 

 Menevian (Upper and Lower) . 

 Harlech group (Upper and Lower). 



ARCH^AN, OR, PRE-CAMBRIAN. 



