viii SYNOPS/S OF CONTENTS. Chapter VI.— MENEVIAN Group. PAGE PAGE Menevian beds, stratigraphical re- j Genera which first appear in the lations of . . . . .41 Menevian beds ... 42 Menevian trilobites . . . 41 Foreign representatives . . 43 j Palaeontology of the Menevian beds 43 Chapter VIL—Lingula Flags and Tremadoc Rocks. Lingula flag group . . *45 IMaentwrog group. ... 45 Ffestiniog group .... 46 Dolgelly group .... 47 Change in the trilobitic fauna . 47 Foreign representatives . . 47 Palaeontology of the Lower Lingula flags 48 Palaeontology of the Upper Lingula flags ...... 50 Shineton shales .... 52 Tremadoc rocks of South Wales . 53 Tremadoc fossils, characteristic . 54 Tremadoc rocks, palaeontology of Lower ..... 54 Tremadoc rocks, palaeontology of Upper . . 55 Summary of Lower Cambrian life 56 Chapter VIII.— ARENIG or Skiddaw Series. Geographical distribution Arenig rocks of North Wales „ South „ Sequence of the Arenig rocks Arenig fauna .... Palontology of the Arenig group 57 Distinctiveness of the Arenig fauna 65 58 ! Comparison of the Arenig areas . 66 59 The Borrowdale series . . 66 61 Dufton and Swindale shales • . 67 62 I Sequence in the Lake district . 67 63 Relation to volcanic rocks . . 68 Chapter IX.—Lower Bala and LLANDEILO Flags. The three classical localities— Llandeilo, Builth, and Aber- eiddy Bay .... The St. David’s area . Fauna of the Llandeilo series ! Moffat or Scotch Graptolite shales 71 ' Zones of the Scotch Rhabdophora 72 69 Palaaontology of the Llandeilo 70 . rocks . . . . -73 70 j Chapter X.—Caradoc Sandstone, Bala Beds, and Coniston Limestone. Historical notice .... 76 The Bala beds as grouped in the Woodwardian catalogue . • »71 Coniston limestone — position, fauna, and conditions of deposi tion 78 Graptolitic mudstones—the Skel- gill beds ..... 80 Mudstone fossils and their foreign representatives. . . .81 The Knock beds . . . .81 Chapter XI.—Palaeontology of the Caradoc Rocks. Numerical value of the Caradoc fauna ..... 82 Geographical distribution of Cara doc species . ... 84 Distribution in time of Caradoc species ..... Palteontology of Caradoc rocks . 85 85