INTRODUCTION 429 



Page 



Neopaleozoic era 532 



Siluric or Ontario period 532 



Devonic period 540 



Mississippic period 547 



Tennesseic period 552 



Pennsylvanic-Perrnic period 555 



Mesozoic era 576 



Triassic period 576 



Jurassic period 580 



Cornanchic period 583 



Cretacic period 587 



Tertiary or Neozoic (Cenozoic) era 597 



The new geologic time table 600 



Introduction 



It is now nearly thirty-eight years since the writer found his first fossil 

 at Cincinnati, Ohio, during the past twenty-four years of which he has de- 

 voted his entire time to invertebrate paleontology and Paleozoic stratigra- 

 phy. His professional service in these sciences had its initiative in associa- 

 tion with E. 0. Ulrich, and was continued with James Hall, C. E. Beecher, 

 and Charles D. Walcott. Subsequently nearly all the larger American col- 

 lections of Paleozoic fossils, as well as many European ones, have been 

 examined or studied by him. For eleven years he had charge of the un- 

 rivaled collections assembled through the various government surveys, 

 which are now deposited, together with much other material, in the 

 United States National Museum. It was during these years of paleon- 

 tologic abundance, grand library facilities, and the enthusiasm engen- 

 dered through daily association with eleven paleontologists that he began 

 the investigation of the problem of interprovincial correlations. The 

 greatest stimulus toward determining the provincial value of fossils came 

 in 1894, from reading Suess's celebrated work "Das Antlitz der Erde." 

 Observations of the kind noted by Suess became sufficiently frequent by 

 the year 1900, so that when Ulrich removed from Newport, Kentucky, to 

 Washington, the inspiration of his presence, together with his detailed 

 knowledge of the older Paleozoic periods, led to the publication in 1902 of 

 "Paleozoic seas and barriers in eastern North America," this paper being 

 the first joint expression on inter-regional correlations by UMch and 

 Schuchert. From this time on, and especially since his appointment at 



2 Teachers and others may obtain of the writer, at cost, copies of the paleogeographic 

 maps as here printed, as well as of two types of blue-prints of the original maps, size 

 20 by 26 inches ; also lantern slides. 



