Makylaxd Geological Survey 77 



Konieprusian. In his paper on tlie Lower Devonic Aspect of the Lower 

 Helderberg and Oriskany Formations, he stated : " Each region has, of 

 course, its own development, and the common forms of one region may 

 be rare in the other. For instance, in America the great development 

 .... of Dalmanella and Ehipidomjella " has but little variation in the 

 Konieprusian, " while here the spire-bearing families Meristellidai and 

 Athyridge have a far greater diversity. The same is also true for the 

 Rhynchonellidse, although these shells are varied and abundant in the 



Lower Helderberg The great diversity of the fenestelloids " in the 



Konieprusian " is in harmony with a similar development " in the 'New 

 Scotland. " The stromatoporoids are also in harmony with this view. The 

 trilobites do not oppose this correlation, but two characteristic species of 

 the Lower Helderberg — Dalmanites micrurus and Acidaspis tuherculata 



— 'find their equivalents in the next higher zone, or etage G The 



writer therefore concludes that the Konieprusian (Fj) and the Lower 

 Helderberg are the equivalents of each other and represent the best known 

 lowest Lower Devonian faunas." ' 



The Oriskany equivalents are not present in southern Europe and if, 

 as is probably true, this time is represented by faunas, they are very unlike 

 the American development. Nor is the southern Oriskany life — the Cam- 

 den of the Mississippian Sea — present in Europe, yet when the typical 

 Oriskany and more especially the Gaspe faunas are compared with those 

 of the Coblenzian of northern Europe, the faunal connections are at once 

 convincing and indicate that migration between these areas took place 

 by way of the north shore of Poseidon or the North Atlantic. 



In reviewing the various efforts of American geologists to classify the 

 formations now comprising the Lower Devonian, it is not necessary to go 

 back farther than the year 1843. The epoch-making work of the New 

 York State Survey vras at that time completed, and the geologic section of 

 that State has since been regarded as the " standard " of correlation for 

 most of the other American and the Canadian Paleozoic areas. In the west- 

 ern part of New York State are to be seen the longest Devonian sections, 

 yielding an abundance of organic remains. There is, however, almost no 



' Schuchert, BulL Geol. Soc. America, vol. xi, 1900, pp. 264, 265. 



