108 SIXTEENTH REPORT ON THE CABINET OF NAT. HISTORY. 



The term " CatskiU group or Old Red Sandstone,''^ as applied in the 

 central and western part of the State to some red beds occurring as outliers 

 on the summits of the higher hills, and in a continuous formation beyond 

 the limits of New-York in Pennsylvania, is not at all applicable to any 

 bed in the CatskiU mountains below the elevation of the Mountain House. 

 It becomes, moreover, problematical whether anything more than the coarse 

 conglomerate of the upper part of the Catskills can be properly designated 

 CatskiU group. 



The fossil plants, therefore, which were derived from places heretofore 

 regarded as authentic localities of the CatskiU group must all be referred 

 to the preceding formations of the Hamilton and Chemung groups. Even 

 the typical locality of Mount Upton must, I believe, give way before the 

 evidences now accumulating ; and the species of fossil plants will occupy 

 but two stages, unless we recognize those of the Genesee slate as an inter- 

 mediate group to the Hamilton and Chemung. 



The arrangement of the list given by Professor Dawson would then be 

 modified much as follows : * 



UPPER DEVONIAN. 



Chemung and Portge Groups. 



Aporoxylon. 



Lepidodendron chemungense, Hall. 

 L. corrugatum, Dawson.^ 



L. gaspianum, Dawson. 



Sigillaria vanuxemi, Gceppert. 

 Syringodendron gracile, Dawson. 

 Stigmaria exigua, Dawson. 



Lycopodites vanuxemi, Dawson. 



Cyclopteris jacksoni, Dawson. 



C halliana, Gceppert. 



Psilophyton prii'ceps, Dawson. 



Rhachiopteris, Dawson. 



R. striata, Dawson. 



R. punctata[?], Dawson, 



MIDDLE DEVONIAN. 

 Hamilton Group. 



Syringoxylon mirabile, Dawson. 



Dadoxylon hallii, Dawson. 



Aporoxylon. 



Sigillaria simplicitas, Vanuxem. 



Sigillaria. 



Didymophyllum reniforme, Dawson. 



Calamites transitionis(?), Gceppert. 



C. inornatusj, Dawson. 



Lepidodendron gaspianum, Dawson. 



Psilophyton princeps, Dawson. 



Cordaites robbi(?), Dawson. 



Cordaites ( s.n.). 



C. angustifolia. Dawson. 



Cyclopteris incerta, Dawson. 



Rhachiopteris tenuistriata, Dawson. 



R. pinnata, Dawson. 



R. punctata(?), Dawson. 



Acanthophyton spinosum, Dawson. 



• Prof. Dawson has added to his paper a note making corrections which correspond 

 essentially with those introduced in the table. 



t This and Rhachiopteris striata, cited as from the Hamilton group of Akron, Ohio, 

 have been thus cited through some mistake. The beds at Akron are of the age of the 

 Chemung of New-York, or the Waverly sandrtone of Ohio, I have accordingly placed 

 them in their proper position. 



X This species should more properly be placed in the Genesee slate and Portage 

 group. The same species occurs on the Genesee river, in the black shales alternating 

 with green shales at the base of the Portage group; and also on the shore of Lake 

 Erie at Eighteen-mile creek, and between that place and Sturgeon point, in the black 

 and dark greenish shales of the Portage group, which correspond with those of Kettle 

 point oa Lake Huron. 



