66 THE DEVONIAN AND CARBONIFEROUS. [bull. 80. 



didial, Medidial, Post-medidial, Ponent, Fesjyertine, Serai series; the deposits of the 

 Dawn, Morning, Suurise, Forenoon, Noon, Afternoon, Sunset, Evening, and Twilight 

 periods of the great Appalachian Paleozoic day. 



The author goes to some length in explaining the application of this 

 scheme to the formations of the "Appalachian system" and their cor- 

 responding limits in the formations of the New York geologists, and we 

 notice that he has attempted to cover very much the same field already 

 covered by the nomenclature of the New York State survey. The ad- 

 vantages of his nomenclature it seems to the writer are entirely nega- 

 tive; the names are entirely arbitrary, and on that account have not 

 the objections attaching to them which were raised against mineralogic 

 or paleontologic names. The greatest objection to the scheme as a 

 whole is that it is necessarily local, both geologically and geograph- 

 ically, since it is a scheme of nomenclature which does not permit inter- 

 calations without disturbing its symmetry, and it does not allow of 

 expansion to cover what might be found below or to cover the higher 

 rocks. 



The author discussed in the latter part of his address the formations 

 of the Mesozoic period, named the Red sandstone along the eastern 

 border u Mesozoic Red sandstone,' 71 and enumerated some of the fo'ssils 

 occurring in the " Mesozoic Coal Measures of Eastern Virginia." The 

 Cretaceous deposits are briefly referred to and a few of their charac- 

 teristic fossils enumerated. The Cainozoic or Tertiary period is also 

 briefly described, and above that the Post-Pliocene period is reported in 

 Maryland and North Carolina and elsewhere along the coast, aud a few 

 of the fossils which Conrad had been so active in describing are named. 



In 1847 Daniel Sharp 2 reported the Oriskany sandstone, Cauda Galli 

 grit, and Schoharie grit as locally distributed in New York, the first 

 being most prominent in Pennsylvania and Virginia. The whole series 

 is classified in the Devonian system. 



The Marcellus shale, the Hamilton group (Moscow shales, Eucrinal 

 limestone, Ludlowville shales), Tully limestone, and Genesee slate are 

 especially distinguished by their faunas, which consist chiefly of Brach- 

 iopods and Lamellibranchs, the majority of them peculiar to the De- 

 vonian while a few occur in the higher Carboniferous deposits. This 

 is by far the most fossiliferous series in the Devonian system. The 

 Portage group, consisting of sandstones and shales aud having a thick- 

 ness of 1,000 feet, is nearly barren of fossils, while the Chemung rocks, 

 which have a thickness of 1,500 feet and occur just above the Portage 

 group, are highly fossiliferous. Both of these series are considered as 

 belonging to the Devonian system, and with the Hamilton group con- 

 stitute the "Erie division." The Devonian system closes with the 

 Chemung group, above* which comes the Old Red sandstone formation. 



1 Am. Jour. Sci., vol. 47, 1844, p. 247. 



2 Sharpo, Daniel : Report on the fossil remains of mollusca from the Taleozoic formations of the 

 United States (etc.), with remarks on the comparison of the North American formations with those of 

 Europe. Quart. Jour. Geol. Soc, 1847, vol. 4, pp. 145-181. 



