DEVONIAN. 311 



the abundant Devonian fossils of the formations outcropping in that region. The first attempts 

 to define the separate faunules and to apply names to them were imperfect on accoimt of the 

 absence then of any knowledge as to the range, distribution, and relative abundance or rarity 

 of the component species. These statistics were gathered as the investigations progressed. 

 Although those first attempts at classification on the new basis are now superseded by classifi- 

 cation based on the full appreciation of the laws of shifting of faunas, the record of the steps 

 by which the progress has been made will indicate how from the study of conspicuous local 

 phenomena broad general laws have been developed. 



Williams enumerates the several classifications developed for the Upper 

 Devonian by the special f aunal studies, and finally says : 



Revising this classification now in the fight of the fuller exhibition of the facts, some of 

 the distinctions made in 1885 are believed to be too refined and local for perpetuation in a general 

 classification, but a few of the points then made may be adopted for general use in discussing 

 the faunas of the whole continent and in comparison with the faunas of the world. 



The fauna of the typical Hamilton formation (A) may be appropriately called the Tropi- 

 doleptus carinatus fauna. That species is more characteristic of the fauna as it appears in its 

 purity in the eastern New York province than is Spirifer (mucronatus) pennatus Atwater. 



The second fauna, of the Black shales (B), may be appropriately called the Lingula spatulata 

 fauna, as that species is characteristic of it far and wide when in its purity, is rarely entirely 

 absent, and may be found, if difigently searched for, in a typical black Devonian shale almost 

 anywhere in the interior continental basin. 



The third fauna, of the Portage shales (C), may be called the Cardiola speciosa fauna. 

 Although, as Hall has shown, this is not a Cardiola, as strictly interpreted, and the name Glypto- 

 cardia was proposed as a new generic name in 1885 to take its place, the fact that in Europe 

 as well as in this country this generic name has been appHed to this species and its European 

 representative makes it not inappropriate as a name for the fauna. As Hall observed in discus- 

 sing this species (Glyptocardia (Cardiola) speciosa Hall): "It is probably identical with the 

 Cardiola retrostriata (von Buch) of various authors, and with Cardium palmatum of Goldfuss. 

 Its citation by numerous authors shows its wide distribution in Europe." 



The fourth fauna of the list (D) — that of the Chemung formation of the east — is the 

 Spirifer disjunctus fauna. The species Spirifer disjunctus is undoubtedly identical, specifically, 

 with the form which is more commonly called Spirifer vemeuili by European geologists. There 

 are several varieties of it which are present in some regions in which the typical form Sp. 

 disjunctus is wanting. 



Regarding the Chemung, HalP^"' said in part: 



This group consists of a highly fossihferous series of shales and thin-bedded sandstones, 

 sometimes in well-defined and distinct courses, and an infinite variety resulting from the admix- 

 ture of the two ingredients. Except in a few locahties, there is no very strongly marked line of 

 division between this group and the one below. The distinction consists in the presence of 

 numerous fossils and the coarser-grained sandstones, winch are usually more impure from 

 argillaceous admixture than those below. Its hthological characters, however, are variable- 

 and though well marked across a single line of section from north to south, still another at a 

 short distance east or west of this presents considerable variation. 



These rocks, however, can everywhere be described as a series of thin-bedded sandstones or 

 flagstones with intervening shales, and frequently beds of impure limestone resulting from the 

 aggregation of organic remains. The whole series weathers to a brownish olive, and even the 

 deeper green of the shales assumes this hue. 



The shales vary in color from a deep black to olive and green, with every grade and mixture 

 of these. The sandstones are often brownish gray or ohve, and sometimes light gray. More 



