SECTIONS OF THE LIAS. 



109 



transition zone, and the Midford a sands, an upper transition zone, 

 the series contains five great groups : 



Transition Zone. Midford sands arenaceous, with sub-calcareous nodules. 



Upper lias Clay or shale, with nodules of ironstone and lime. 



stone. 



True Lias. -| Middle Has Ferruginous rock, partly calcareous, partly arena- 



ceous. 



Lower lias Clays or shales and limestones in many alterna- 

 tions. 

 Transition Zone. Westbury or rhaetic shales and bone-beds. 



Each of the divisions is characterized by peculiar races of am- 

 monites and belemnites, except the lower, which appears to have 

 neither. In the others are several stages or zones of ammonites 

 and belemnites, as well as of fishes and reptiles. 



We may now complete the upper part of the fine section at 

 Wilmcote, near Stratford-on-Avon, which in some respects is the 

 most important of all, since it gives in a compact form the series 

 of liassic beds above the Westbury shales, which for convenience 

 are added below : 



ft. in. 



'Top blocks' o 



I 



SERIES OF LOWER LIAS BEDS. 

 Yellowish clay 

 Limestone, light-coloured. 

 Dark laminated shales 

 Limestone, light-coloured. 'Bottom blocks' o 



Dark shales I 



Limestone, grey. ' Fine course' . . O 



Dark, finely-laminated shale I 



Limestone, grey. ' Mawms' . . o 



Dark laminated shale .... I 



Limestone, grey. ' Top whites' . . o 



Dark shales I 



Limestone, grey. ' Bottom whites' . o 



Dark shale o 



Limestone grey. ' Livery beds ' . o 



Dark shale O 



Limestone, grey. ' Ribs' o 



Dark shale o 



Limestone, grey. ' Hoggs' O 



Dark shale . . . ... 4 



Dapedius ? 

 Ammonites planorbis. 



Am. planorbis. 

 Am. planorbis. 



a This title is suggested for these unnamed sands. They were first discovered and 

 studied by Smith, in the picturesque cliff which overhung his house at Tucking Mill, 

 near Midford. 



