MODIFIED VIEWS OF MTJRCHISON AND SEDGWICK 257 



survey was made, has but led to a much more complete identification of the Rhenish 

 provinces with Devonshire, than that which was proposed by my colleague and 

 myself. In short, it now appears that not some only, as we thought, but all the 

 paleozoic strata of Devon have their equivalents on the banks of the Rhine. 80, 

 that, starting from the North Foreland of the British channel, and ascending into 

 the heart of the culm fields, . . . the geologist has before him the successive 

 representatives of the Rhenish deposits. 



" Those persons who may refer back to the sixth volume of the Geological Trans- 

 actions of London, will, therefore, understand that all the Rhenish ground which 

 is described or colored in the map and sections as Upper Silurian, is now embodied 

 in the Devonian rocks; whilst to their admirable description of the fossils MM 

 d'Archiac and de Verneuil have but to add the one plate of the few so-called Silu- 

 rian fossils, to their thirteen plates of true Devonian types, and all the general 

 features of our labors will be in harmony with subsequent observations." * 



LOWER DEVONIC OF GERMANY AND THE AMERICAN EQUIVALENTS 



Vieius of writers as to its extent, character, and divisions. — Writing of the 

 Lower Devonic of the Rhine, Kayser says : 



"This consists of at least 10,000 feet of sandy and clayey beds, almost entirely 

 free from lime. The fossils which occur in it are almost always mere stone-casts. 

 . . . They are generally rare, and are found only in isolated beds, which are 

 often separated by many hundred feet of practically unfossiliferous rock. The 

 fauna consists chiefly of Brachiopoda. The only other important forms are La- 

 mellibranchs, Crinoids, and some Trilobites and Gasteropods, while Cephalopods 

 and Corals are few in number. Some species ... go through the whole, or 

 almost the whole, series of beds, whilst others have a more restricted range. In 

 general the constitution of the fauna points to a shallow sea, and the ripple-marks 

 frequently met with at all horizons also speak in favor of this view." f 



Freeh J writes that students of Rhenish geology are agreed on the 

 following divisions of the Lower Devonic of Germany, which have for 

 their bases four species of prevalent brachiopods : 



{c. Zone with S. speciosus = ~Red ironstone. 

 b. Upper Coblenzian. 

 a. Coblenz quartzite. 



{b. Lower Coblenzian. 

 a. Porphyroid and Grau- 

 wacke of Sendorf. 



{Gedinnian. 

 T Q fSericitglimmerschiefer. 



launus. < r r _-,_„_ n i 1Tr ii; fn 



n e c, . .j. . f Siegen. f 6. Hunsriick schiefer. 



Zone of Spmfer pnmxvus . . ( Gr | uwacke< { (L Taunua quartzite . 



f Sericitglimmer s( 

 \ Taunus phyllite. 



* Murchison's Siluria, pp. 365, 366. 



fKayser's Text-book, 1893, p. 92. 



% Lethsea geognostica, 1 Theil, 2 Band, 1 Lief., Stuttgart, 1897. 



XXXVIII— Bum,. Gkol. Soc. Am., Vol. 11, 1899 



