VERTEBRATE FOSSILS 575 



I. The horizon of the Clepsy drops shales of Illinois and the corresponding 

 beds in Texas is Permian. 



Finally in 1879, in a comparison of the vertebrate horizons of 

 Europe and America/ he gave the following table: 



West Europe North America 



Thuringian ) p . \ Clepsydrops shale 

 Lodevian \ ^^"^ ^ \ Eryops beds 



And says : 



The Permian vertebrate fauna which I discovered in Illinois and Texas 

 exhibit close parallels, but not yet generic identity, in the two continents. Thus 

 the American Clepsydrops and Dimetrodon are near to the Deuterosaurus of the 

 Perm of Russia, and the Lycosaurus of the mountains of South Africa. The 

 Texan genus Pariotichus may, with further information, prove to be identical 

 with the Procolophon Ow. from the Tafelberg. Humeri of the t)^e discovered 

 by Kutorga in Russia and by Owen in South Africa, are found in North America, 

 and the same remarkable type has recently been discovered by Gaudry in France. 

 The peculiar type of Labyrinthodont vertebae described by me under the genus 

 Rhachitomus from Texas has been discovered by Gaudry in France. The present 

 indications are that close similarity between the faunae of this period in Europe 

 and America will be discovered. Nevertheless up to the present time no repre- 

 sentatives of the striking American forms, Diadectes, Bolosaurus, Empedocles, 

 and Cricotus, have yet been found in any other continent (p. 34). 



The oldest of these I have called the Eryops beds, from the most abundant 

 genus of Labyrinthodonts which is found in it. They contain also abundance 

 of other vertebrata, none of which are higher than the reptilia (order Thero- 

 morpha), with plants, mollusks, etc. They consist of sandstones, alternating 

 with beds of red clay and coarse conglomerate and sphaerosiderite, etc. They 

 are chiefly distributed in Northern Texas and Southern Indian Territory. 



The Clepsydrops shale named by me in 1865 [misprint for 1875] forms a 

 thin stratum, in southeast Illinois and southwest Indiana, consisting of black 

 and rarely reddish carbonaceous shales and clays. These appear in some places 

 to lie conformably upon the Coal Measures, to which they have been referred 

 by previous geologists, but Collett, Gibson, and others have shown that it is 

 unconformable over considerable areas. It does not belong to the Coal Meas- 

 ures (p. 52). 



After this paper Cope consistently referred to the beds as Permian. 

 Reviewing the evidence cited above we find that the beds were so 

 referred on — 



I. The presence of reptiles. 



I Bull. Geol. and Geog. Survey of the Terrs., 1878-79, pp. 33-54. 



