542 REPORT OF NATIONAL MUSEUM, 1904. 



Beginning with the later Tertiary times, the following sequence of 

 events was established: 



(a) In the Miocene and Pliocene epochs a continent several hundred 

 feet lower than now, the ocean reaching to Louisville and Iowa, with 

 a\subtropical climate prevailing over the lake region, the climate of 

 Greenland and Alaska being as mild as that of southern Ohio is now, 

 while herds of gigantic mammals ranged over the plains. 



(h) A preglacial epoch of gradual continental elevation which cul- 

 minated in the glacial epoch, when the climate of Ohio was similar to 

 that of Greenland at present, and glaciers covered a large part of the 

 surface down to the parallel of forty degrees. 



(c) This period was followed by another interval of continental sub- 

 sidence characterized by a warmer climate and melting of the glaciers 

 and by inland fresh-water seas tilling the lake basin, and in which 

 were deposited the Erie and Cham plain cla}^s, sands, and bowlders. 



{(I) Another epoch of elevation which is still in progress. 



Much attention was given to economic geology and the study of the 

 coal beds. From analyses it was shown that the change from woody 

 tissues to peat or lignite, and thence to bituminous and anthracite coal 

 and plumbago consisted in the evolution of a portion of the carbon, 

 hydrogen, and oxygen, leaving a constantly increasing percentage of 

 carbon behind. This evolution Newberry conceived to be due to the 

 disturbances which resulted in the uplifting of the mountain chains 

 and metamorphosed the included rocks. 



The coal beds of Ohio, it should be noted, were considered as 

 always having been separated from those of Illinois b} T the Cincin- 

 nati anticline. This Cincinnati uplift or arch was, in the report for 

 1869, regarded as having formed a land surface over a considerable 

 portion of its length at least during the earlier and probably through- 

 out all the Devonian ages. Later, in discussing the work of Orton 

 in Adams County, Newberry wrote: 



Here we have an indubitable record of the elevation of the Cincinnati arch between 

 the Upper and Lower Silurian ages, and proof that it in far older than the Appala- 

 chian system, with which it haw been commonly associated. 



The carbonaceous matter of the Huron shales was suggested as 

 probably due to an abundance of seaweeds which flourished in a kind 

 of Saragossa sea which occupied that region during the period of 

 deposition. 



The petroleum and gas tilling the cavities and interstices in the 

 sandstones and conglomerates in the Oil Creek region were regarded 

 as not indigenous to those rocks, but rather as originating in the 

 lower-lying Huronian shales, from whence they had been forced 

 upward by hydrostatic pressure. 



The dolomitic character of the rocks of the Clinton, Niagara, and 

 Water-lime series was ascribed to u a vital rather than a chemical or 



