288 IDENTITY OF THE WESTERN FORMATIONS 



dition and character of the ocean during the earlier geological 

 periods. 



The great extent of almost undisturbed strata affords an oppor- 

 tunity for the most satisfactory investigations, throughout all this 

 country. The anticlinal axis which is crossed by the section 

 near Cincinnati, is an important feature. By the elevation of this 

 axis, the higher rocks have been removed, and the two great coal 

 basins of Ohio and the Wabash valley (formerly in all probabihty 

 constituting one) are thus separated from each other. This axis 

 extends in a direction northeast and southwest; and passing along 

 the western part of Ohio, and crossing Lake Erie near its west- 

 ern extremity, it gives origin to the numerous islands of this part 

 of the lake. It extends onward into Canada, and I understand 

 from the Messrs. Rogers, that they have traced it far northward in 

 that province. To the southward it passes through Kentucky 

 and Tennessee, and at Frankfort, in the former State, elevates 

 the Trenton and birdseye limestones above the level of the river. 



The section crosses a synclinal axis which runs nearly parallel 

 to the great anticlinal one, but its extent is unknown to me. The 

 Wabash flows in this depression, which brings the coal-bearing 

 strata below the level of the Ohio river, at its junction with the 

 former. From this point the strata are seen to rise to the westward 

 as far as the Mississippi, but beyond little is known of them. 

 From the occurrence of extensive coal deposits in JVIissouri, it 

 may be presumed that the strata decline to the southwfest, but 

 I have no data from actual observation on which to found an 

 opinion. 



From the necessarily hasty examinations made during this tour 

 of exploration, which was extended over a large area, it was im- 

 possible to give that minuteness of detail, which is desirable before 

 the subject can be considered complete. All that was attempted 

 was to trace the great groups of New York westward, and, if 

 possible, to identify them with those known by different names in 

 that part of the country. If any light has been thrown upon this 

 question, or if only some few points of identity have been estab- 

 lished, the object will have been accomplished. In this vast field 

 there is room for all the laborers that can be found for half a 



