INTRODUCTION. 5 



SECONDARY EPOCHS (continued.) 



Portland beds. (Isle of Portland. Swindon.) 

 l> Bucks) 



I-, . , ,, /Coral rag. (Wilts. Gloucestershire, &c.) 

 OOLITIC \ mi( lie> \0xford clay. (Christian Malford. Trowbridge, Wilts.) 



or ) /Cornbrash. (Wilts. Gloucestershire.) 



JURASSIC } I Forest marble; Bradford clay. (Bradford, Wilts.) 



FORMATION.] T ._-_ /Great oolite. (Bath.) 



I lj wer -\ Inferior oolite. (Cheltenham.) 



IFluvio-marine intercalations. (Scarborough. Stonesfield, Ox- 

 \ \ fordshke. Collyweston. Brora, Scotland. 



AJpper Lias. (Lyme Regis, Dorset.) 

 LIASSIC J Lias marlstones. 



FORMATION. j Lower lias clays, shales, and limestones. (Gloucestershire. 

 V Somersetshire.) 



fVariegated marls, red sandstones, &c. (Liverpool.) 



IRIAS c ) Gypseous marls; beds of rock salt. 



) Fawn-coloured limestones. (Upper Bunter, and Muschelkalk, 

 FORMATION. (^ of Germany.) 



PALAEOZOIC EPOCHS. 

 Lower red sandstones. 



T, \ Magnesian limestones. (Zeichstein. Lower Bunter, Keuper- 



fE i*. i 



FORMATION I { Schiefer or Copper Schist of Mansfeld, Germany. County 

 . Marl slates, and brecciated limestones. 



{Coal measures. (The principal depositories of the flora of the 

 Palaeozoic epochs.) 

 Millstone grits. 

 Mountain or carboniferous limestone. (Derbyshire.) 



P. ' fRed and yellow sandstones and Quartzose conglomerates. 



(Devonshire. Cornwall. Herefordshire. Forfarshire, &c.) 

 (or OLD RED) ( Cornstones ^ marls . 

 FORMATION. ^ T ii es tones. 



(Ludlow rocks and Aymestry limestone. (Herefordshire and 

 /Yr ) Shropshire.) 



SILURIAN u PP er - \ Wenlock or Dudley limestone. 

 VShales. 

 f Caradoc sandstones. 



FORMATION^ VShales. 



T *~ 

 M.ower. Llandeilo fla g s . (Caermarthenshire.) 



CUMBRIAN (Slaty rocks with few traces of organic remains. (Cumber- 

 FORMATION. \ land.) 



1 The separation of the strata now termed Permian from the Triassic 

 group, with which they were formerly classed, was first proposed by Sir 

 Roderick Murchison, and is based on the fact that the fossils hitherto 

 discovered are entirely distinct from any that occur in the Trias and 

 subsequent formations : it is, therefore, inferred that after the deposition 

 of the so-called Permian strata, a complete change took place in the 

 faunas and floras of the lards and seas, and the Trias is regarded as the 

 dawn of a new system of organic beings.* 



* The reader interested in this subject should refer to an able "Mo- 

 nograph on the Permian Fossils of England," by Professor William 

 King, of Queen's College, Galway, recently published by the Palaeonto- 

 graphical Society of London; 1850. See also Sir Charles Lyell's 

 " Manual of Elementary Geology," 1851, p. 301. 



