122 



INDIANA UNIVERSITY STUDIES 



moth Cave and is another example of the solubility of the Mitchell 

 limestone. The Harrodsburg, Oolitic or Salem, and the Mitchell 

 limestones are shown in Chart No. 1 as one formation. Through 

 this limestone region both forks of White River narrow down to 

 about a quarter of a mile in width. This narrowing of the valley 

 in passing from the region of soft shales and sandstones to the hard 

 limestones had remarkable effect on the flood conditions, as will 

 be mentioned in another place. 



The last division of the Mississippian is the Chester. This 

 consists of a series of thin limestone, shales and sandstones, aggre- 

 gating 190 feet in thickness. There are three thin limestones with 

 sandstone and shales between. 



Coal Measures. The Mansfield sandstone is a massive, 

 coarse-grained sandstone and is the basal member of the coal mea- 

 sures in this State. On top of the Mansfield Sandstone is a series 

 of shales, sandstones, coal seams, fire clays, and limestones. The 

 shales make up the greater part of the coal measures. The Merom 

 sandstone lies next above the coal measures. Mr. J. F. Newsom 

 in the '26th Annual Report of the State Geologist,' says: 'Lying 

 above the productive coal measures and separated from them by 

 an unconformity is a sandstone with a thickness at Vincennes of 

 from 40 to 50 feet. This sandstone has been known as the Merom 

 sandstone, owing to its good exposures at the town of Merom. 

 In general appearance it resembles the Mansfield sandstone, for 

 which it has sometimes been mistaken. Whether it is of carbon- 

 iferous, or later, age has not been satisfactorily determined.' 



It is interesting to note that the size of the valley depends 

 on the material through which the river flows. Above Gosport, 

 on the West Fork, the river flows through the Knobstone region, 

 which is composed of shales and thin bedded sandstones. These 

 shales are easily eroded and as a result the valley is wide; being 

 one to three miles in width. As the Limestone region is reached 

 below Gosport, the valley narrows to between a quarter and three- 

 quarters of a mile, until it leaves the Mansfield sandstone below 

 Bloomfield, where it again widens even more than above Gosport. 

 The same conditions are present on the East Fork. At Sparks- 

 ville the wide valley narrows to a mile or less as it leaves the Knob- 

 stone region and enters the limestone area, and continues very 

 narrow until it leaves the Mansfield sandstone at Shoals. Thus 

 there is a remarkable constriction in the valleys of both forks where 

 they flow through the limestone rocks and the more resistant Mans- 

 field sandstone. It may be stated that House Rock and Jug Rock, 



