6 CONTENTS 



ii. The Old Red Sandstone — continued PAGE 



Deposition in Lakes 177 



Deposition in the Sea 179 



Objections to Lake and Marine Theories 180 



1. Physical 180 



(a) Red Color 180 



(b) Marine Denudation 181 



(c) Salt Indicative of Marine Deposition 182 



(d) Thickness of Deposits 182 



(e) Structural Features 184 



2. Faunal 184 



Summary 186 



Theory of Fluviatile Deposition 186 



Summary of evidence of Fluviatile Deposition 189 



(a) Lithogenesis 189 



{b) Faunal 191 



12. Miscellaneous Occurrences 193 



Chapter V. The Geological and Geographical Distribution of the Eurypterids 



and the Conditions of Migration 200 



Summary of Facts Observed Regarding the Distribution of the Eurypterids 200 



Migration and Dispersal of Recent Fluviatile Organisms 203 



A. Species Identical in Distant Continents 203 



B. Genera Identical in Distant Continents 204 



C. Families Identical in Distant Continents 204 



Summary 205 



Application of Principles Deduced from Modern Faunal Distribution 207 



Migration and Distribution of the Eurypterids 212 



Theory of Early Marine Habitat and Routes of Migration 212 



Objection to Marine Habitat Theory 212 



Theory of River Habitat 216 



The Eurypterid Faunas Considered by Continents 217 



The Eurypterid Faunas of Appalachia . 217 



Comparison of Pittsford and Shawangunk Faunas 225 



Summary of Facts of Distribution in Continent of Appalachia 226 



The Eurypterid Faunas of Atlantica 228 



Comparison of Pittsford-Shawangunk and Bertie Faunas 229 



The Upper Siluric Faunas of the Baltic Region 236 



The Fauna of the Wenlock 238 



Summary of the Wenlock Faunas 242 



The Fauna of the Ludlow 242 



The Old Red Sandstone Fauna 247 



Summary of Facts of Distribution on Continent of Atlantica 253 



The Eurypterid Fauna of Mississippia ' 253 



Concluding Remarks 256 



Bibliography 257 



