THE ONONDAGA SEA IN THE ALLEGHENY REGION 99 



of its sediments. The comparatively thin mass of sediment which 

 accumulated during the whole of the Devonian in the central states 

 affords satisfactory evidence that the land area adjacent to the 

 Devonian sea on the west had slight relief, and furnished compara- 

 tively little sediment at any time during the Devonian. On the 

 east side of the Devonian sea, however, physiographic conditions 

 were very different. Willis 1 has shown that during much of the 

 Devonian period there lay immediately southeast of the Alle- 

 gheny region the highlands of Appalachia. This old land area 

 furnished to the interior Devonian sea of the Appalachian region, 

 between the beginning of the Hamilton epoch and the close of the 

 Devonian, a mass of sediments which, if restored upon a sea-level 

 plain of Appalachia, "would constitute a mountain range closely 

 resembling in height, extent, and mass the Sierra Nevada of 

 California." 2 



According to the prevailing view 3 this fertile source of Devonian 

 sediments was elevated at the close of the Oriskany to such an 

 extent that throughout Onondaga time the Allegheny region was 

 a land area. Such elevation, if it occurred, must have resulted 

 in accelerated erosion in the Devonian highlands, and in an in- 

 creased volume of sediments in the Onondaga sea. If this hypo- 

 thetical uplift occurred, it could not have failed to have been 

 registered by a great thickness of coarse clastic sediments in the 

 narrow Onondaga sea which, as outlined by Schuchert's map, 

 extended as a narrow belt across the adjacent portions of the 

 present states of Kentucky, Indiana, and Ohio. Instead of such 

 coarse elastics we find in these states, as previously noted, only 

 limestones representing sedimentation near the eastern shore of 

 the Onondaga sea as outlined by Schuchert. 4 The utter impossi- 

 bility of harmonizing the pure limestone deposits representing the 

 Onondaga in the Ohio valley with this currently accepted theory 

 of diastrophism in the Allegheny region would appear to be a suffi- 

 cient reason for discarding it. If, however, we assume that Appa- 



1 Md. Geol. Survey, Special Publication, Vol. IV, Pt. I, pp. 61-62. 



2 Ibid., p. 62. 



3 Charles Schuchert, " Paleogeography of North America," Bull. Geol. Soc. Am., 

 XX (iqio), 492. 



4 Ibid., PI. 75. 



