276 



SCIENCE. 



[N. S. Vol. III. No. 60. 



kansas being a trough of erosion between 

 the two highland areas, ' due partly to struc- 

 tural peculiarities, but it is also due largelj'' 

 to other conditions,' the latter not being 

 specified. " As a unit, the Tertiary pene- 

 plain was bowed up from the Red river to 

 the Missouri." 



It has for some time been desirable to fix 

 the date of the Ozark peneplain, but un- 

 fortunately the evidence by which a Ter- 

 tiary date is here assigned to the comple- 

 tion of the peneplain and a Post-Tertiary 

 date to its uplift and dissection is not 

 fully stated. The narrowness of the val- 

 leys may, however, certainlj'- be taken to 

 ■ emphasize the fact that the Ozark uplift of 

 . to-day is essentially modern.' 



HIGH LEVEL GEAVELS OF KENTUCKY. 



The rolling limestone uplands of the 

 blue-grass region of Kentucky, rimmed 

 around by sandstone escarpments on the 

 south, and dissected by deep narrow valleys 

 of streams that flow to the Ohio on the 

 north, are strewn over at various places 

 with gravels and sands. The distribution 

 of the gravels is discussed by A. M. Miller, 

 of Lexington, Ky. (Amer. GeoL, XVI., 

 1895, 281-287). These loose materials are 

 water-worn and bedded, and are derived 

 mostly from the harder rocks of the enclos- 

 ing escarpments ; they are found chiefly 

 near existing valleys. Miller concludes 

 that within comparatively recent times the 

 rivers were flooded to a height of 300 to 

 350 feet above their present channels. In 

 explanatiou of such flooding, a glacial ob- 

 struction of the Ohio is considered as a 

 possibility, but satisfactory evidence is not 

 found in favor of it. ' Submergence ' of un- 

 specified nature is also mentioned without 

 reaching any definite conclusion about it. 



No consideration is given to the possibil- 

 ity that the gravels may have been spread 

 over the upland surface before the present 

 canyon-like valleys were eroded, while the 



whole region stood at a lower level than at 

 present, but not submerged. This is em- 

 inently possible, for the aspect of the blue- 

 grass region is strongly suggestive of base- 

 levelling during a former lower stand of the 

 land, and of dissection after elevation to 

 the present altitude, as has been suggested 

 by Westgate (Amer. GeoL, XL, 1893, 

 258-259). The prepossession that the up- 

 land gravels could not endure for so long a 

 time as would be needed to carve the can- 

 yon-like valleys is not well supported. Old 

 river gi-avels lie on rock benches enclosing 

 the gorge of the upper Ohio ; and in similar 

 position on the valley slopes of the Meuse 

 in its transverse path across the Ardennes; 

 even the fine loess of the upper bench of the 

 Rhine vallej^ in the Schiefergebirge is older 

 than the narrow gorge of that energetic 

 river. 



CLOUD-BTJEST TEACKS AND WATEE GAPS IN 

 ALABAMA. 



A EEPOET on the Coosa coal field by A. 

 M. Gibson (Alabama Geol. Survey, 1895) 

 gives a description of two great scars on 

 Coosa mountain, produced by cloud-bursts 

 that accompanied the tornadoes of July, 

 1872. On the northwest side of the moun- 

 tain there is a washout sixty feet wide and 

 three or four feet deep, extending down the 

 mountain side. Trees, soil and rocks were 

 all swept down, making great moraine-like 

 heaps at the base of the slope. On the 

 southeast side of the mountain there are 

 several scars of even greater magnitude. 

 From one of these rocks of all sizes were 

 carried down to the low ground and there 

 heaped over ' acres of ground.' One mass, 

 estimated to weigh a hundred tons was 

 carried half a mile (p. 28-30) . 



It is to be regretted that the sanction of 

 State publication should be given a few 

 pages later to an antiquated account of 'Big 

 Narrows ' in Double mountain. " Some con- 

 vulsion of nature must surely have made the 



