FAUNAL TKOVINCES AND REALMS 348 



known to stratigraphy occurred during the early Ordovician in Canadian 

 time — the almost world-wide distribution of the floating group of extinct 

 graptolites closely related to hydroids and known as the Phyllograptus- 

 Tetragraptus fauna. First made known by Hall between 1858 and 1865 

 from material collected near Quebec, Canada, it has been traced widely 

 throughout the Appalachian geosyncline, Arkansas, N'evada, Utah, New- 

 foundland, Wales, Scandinavia, Belgium, France, Peru, Bolivia, i^us- 

 tralia (Victoria), and southern Xew Zealand. Therefore, so far as the 

 graptolite faunas are concerned, we again sj)eak of them as cosmopolitan 

 faunas. 



DEVONIAN PROVINCES 



Lower Devonian faunas. — We will now consider some of the Devonian 

 faunas, since they are well known the world over, and, moreover, are re- 

 plete with paleogeographic information. The Helderbergian faunas of 

 New York and the central Appalachian region were first described by 

 Hall in 1859, and now their total amounts to more than 450 species and 

 varieties. The New York development continues its typical faunal ex- 

 pression through Pennsylvania south into southern Virginia, western 

 Tennessee, and Missouri, into Oklahoma. Everywhere it is the life of a 

 calcareous facies and southern in origin. To the northeast of New York, 

 in the Saint Lawrence embayment, the Helderbergian formations take on 

 a more sandy and muddy character, and their biotas, with a large element 

 of North iVtlantic species, are known from Montreal, Dalhousie, Gaspe, 

 and Newfoundland. 



Just as there are two Helderbergian provinces in North America, so in 

 the same way there are two in Europe, and all four are of Atlantic origin. 

 The southern development, the one in closest relationship with the New 

 York Helderbergian, was long ago described b)^ Barrande, and has since 

 come to be known as the Konieprussian assemblage, while to the north of 

 Bohemia and the Pontian old land are the German equivalents now called 

 the Gedinnian faunas. 



These oldest Devonian faunas are characterized at first by their many 

 Silurian hold-overs, but it is evident that certain of these elements soon 

 begin a rapid evolution into new species and genera that are heralders of 

 a new period of time and a new provincial assemblage. Our correlation 

 values here are, among the braehiopods, the rise of many new stropho- 

 menids, rhynchonellids, spire-bearers, and primitive terebratulids; among 

 the gastropods, the great outburst of capulids, most of which attain to 

 large size ; among the cephalopods, the rise of small goniatites ; and 



