H. S. WILLIAMS— THE CARBONIFEROUS SYSTEM. 19 



will greatly facilitate all attempts to determine the limits of the system in other 

 regions. It is evident that the typical section is the section exhibited in the Pennine 

 range ; and as the name Carboniferous is a misnomer geologically, since we now know 

 that carbon or coal bearing rocks are not confined to the system generally so called, 

 and as the name does not indicate the geographic position of the typical section, it is 

 believed that the adoption of the name " Penninian system," or " Pennian system " 

 (the latter being preferable), may be of advantage to the science. 



This Pennine carboniferous system may be defined, as to geographic position^ as the 

 rock formations of the Pennine range of northern England and equivalent formations 

 in other parts of the world. 



In geologic delimitation the Pennine sj'stem begins with a red sandstone and ter- 

 minates with the upper rocks of the Coal Measures. 



In biologic 'definition its first marine fauna is that of the Mountain ^mestone, and 

 its final fauna and flora are those of the Coal Measures. The brackish fauna of the 

 Old Red sandstone had not ceased at its opening, the characteristic Permian fauna 

 and flora had not appeared at its close. 



Whatever may prove to be the correlation between the Old Red sandstone and the 

 Devonian system, the definition of the Pennine system is explicit in including fishes, 

 such as Holoptychius, characteristic of the Old Red sandstone of Murchison, and is 

 as explicit in the exclusion of the Devonian marine fauna above which its earliest ma- 

 rine fauna belongs. 



The rocks and faunas of what was later called the Permian system are definitely 

 excluded by the original author from the Pennine carboniferous system. The prob- 

 lems of the Devonian Old Red system and of the Permian system must be discussed 

 on their own merits : this original section of the Carboniferous has its relations to 

 each clearly defined. 



In correlating our American rocks, the recognition of the Pennine carboniferous 

 system as typical settles for us several disputed questions. 



The Paleozoic along the Appalachian and eastern border region will find the limits 

 between Devonian and Pennine carboniferous in the following positions : The Che- 

 mung marine fauna is strictly Devonian ; the brackish water fish fauna of the 

 Catskill is as strictly Pennine. Hence the red rocks of the Catskill formation of New- 

 York, the Ponent, Umbral, and Vespertine formations of Pennsylvania, belong tj 

 the Pennine carboniferous. 



When, as in western Pennsylvania and Ohio, the species of the Carboniferous, or 

 Mountain limestone fauna of England, appear to follow the marine Chemung, the 

 line should be drawn between them for a strict correlation. On passing westward the 

 formations called Waverly, Marshall, Kinderhook, Chouteau, containing, as they do, 

 a fauna distinctly related to the Carboniferous limestone fauna, must be placed in the 

 Pennine carboniferous system. 



In Kansas and Nebraska and other localities where the upper Coal Measures gradu- 

 ally assume species of the type described from the Russian Permian, the problem of 

 correlation is definite. Both the stratigraphy and the biologic evidence indicate that 

 there is no sharp division between the representative of the Pennine carboniferous 

 system and that of the Permian system. The division line here must be arbitrarily 

 drawn, and the fact that a system is a local series of formations and not a universal 

 subdivision of the geologic time scale, becomes evident. It is in such cases that the 

 paramount importance of the determination of the geographic position of the typical 

 representative of a system is seen, and the only way to make this apparent to all is 

 by the association of the geographic name with the system. 



