ST. JOHNS OR SALAMONIE MORAINE. 523 



Plains similar to that south of the Wabash River occur in Ohio, south 

 of Beaver River and the Grand reservoir, and also south of the west-flowing 

 headwaters of the St. Marys River. There is also a similar narrow plain in 

 northeastern Indiana, between this moraine and the Wabash moraine. The 

 latter moraine is nowhere, so far as yet traced, coalesced with the Salamonie. 

 Yet it is nowhere distant from it more than 10 miles, and usually but 2 to 

 4 miles. 



OUTER BORDEB PHENOMENA. 



As akeady noted, the Mississinawa moraine is closely associated with 

 the Salamonie from the Wabash River in eastern Indiana northward as far 

 as the study has been carried (to the Michigan line), but from the Wabash 

 southeastward to Ohio there is a plain traversed by the Salamonie River, 

 which makes an interval of 4 to 8 miles or more between the moraines. 

 This plain stands at a lower elevation than the bordering moraines, and 

 presents the appearance of a large valley when viewed from either moraine. 

 That it was produced by the accumulation of drift in its borders and not 

 by erosion was noted by McCaslin, who aptly remarks, in his report on 

 Jay County, that its lower elevation, as compared with the moraine, is not 

 due to erosion, for if such were the case it would be bowlder strewn, but 

 bowlders are even more rare here than upon the moraine. 



This plain does not carry a continuous coating of gravel and sand, 

 though it appears to have been the line of escape for nearly all the water 

 from the terminal portion of the ice lobe. Gravel and sand are, however, 

 extensively spread over it near Portland, probably as a dependency of the 

 moraine. At Camden, also, near the point where the belt of large gravel 

 knolls in western Jay County comes to the river, there is a delta-like 

 gravel deposit covering- a square mile or more. Below Jay County the 

 bluff's of the Salamonie have frequent exposures of rock ledges. The di-ift 

 capping the ledges and occupying the depressions between them is mainly 

 gravel, though places were noted where there is a capping of till. Whether 

 the gravel is, in large measure, of earlier age than the moraine or is a 

 dependency of it was not satisfactorily determined. The amount of gravel 

 and sand along the Salamonie is much greater than is found along the 

 Mississinawa or along the Wabash or St. Marys rivers. This is in keeping 

 with the structure of the moraines that follow these streams, the Salamonie 

 being far more plentifully supplied with gravel than any of the others. 



