28 GEOLOGY OF OHIO. 



stated to have been formed " during the ice period, or at an earlier date." 

 On page 12, of Chapter XXX, it is said, " Some of the channels were 

 in part formed long anterior to the ice period, as all of the area of the 

 Eastern, Middle, and North-western States has been a land surface 

 traversed by drainage lines since the close of the Carboniferous period. 

 We may, therefore, conclude that many of our great arteries of aqueous 

 circulation have been in action all through the Mesozoic and Tertiary 

 Ages. The continmd study of these interesting features in our Surface 

 Geology, has led to the conclusion that most of these buried river chan- 

 nels are pre-glacial, and that they form, as suggested in the quotation 

 above, a portion of the surface erosion, suffered by this part of the con- 

 tinent during several geological ages. The facts upon which this con- 

 clusion is based are — 



1st. Many of these channels are deep and narrow gorges, such as are 

 produced by running streams, and not by glaciers, and these bear no ev- 

 idence of ice action. 



2d. They are found south of the line to which the glaciers reached, 

 and in that region ice could have taken no part in their formation. 



3d. Some of them have been filled and obliterated by the bowlder 

 clay, showing that these were river channels which antedate the ice 

 period. 



Many of these old channels have, however, been filled with and modi- 

 fied by ice, as the valley of the Cuyahoga, the bottom of which is glaciated 

 at Boston, twenty miles from its m'^uth. In this instance the direction 

 of the valley accorded with the line of motion of the great glacier which 

 passed across the lake basin, and it is probable that all the old channels 

 within the glacial area that had a north southerly direction, have been 

 occupied and modified, like the valley of the Cuyahoga, by some portion 

 of the ice being pressed into and moving through them. It is probable, 

 also, that the lines of these old channels were frequently followed by 

 local glaciers, as they would then as before be channels of drainage, and 

 the consolidated water would naturally move along the lines of lowest 

 levels, as fluid water had done. As was suggested in the second volume, 

 it is even probable that the basins of Lake Erie and Lake Huron were 

 formed by local glaciers, which followed and enlarged pre existing river 

 , valleys. 



Prof. E. B. Andrews prefaces his report in Vol. II with some pages 

 devoted to surface geology, in which he alludes to these buried channels. 

 On page 45, after referring to the facts cited by the writer, he says: 



The larger streams in llie Second District, (south-eastern rinarterof Ohio) hafl, at some 

 time antecedent to the Drift era, large portious of their beds deeper than now, as shown 



