286 Dr. John T. Plummet on the 



be composed chiefly of fragments of granite, jasper, limestone 

 slate, hornstone, and greenstone. The diluvium which fills up 

 the remainder of the channel is about ten feet thick immediately 

 over the silt, and is the same that forms the general surface of 

 the country ; bowlders however are much more numerous in the 

 course of the obliterated stream than in any other part of the 

 diluvium exposed to view by the cut for the road. These bowl- 

 ders are from both primitive and fossiliferous rocks ; several large 

 flat pieces of blue limestone containing exuvise were found among 

 them, thoroughly smoothed on both sides, and rounded at the 

 ■edges. Among the fossils I have not been able to discover more 

 than two species which are not common to the neighboring 

 rocks ; yet from their being so greatly worn on every part, and 

 accompanying the primitive bowlders, and indeed from some of 

 them lying above the level of the adjoining strata, it is highly 

 probable that they were transported from some distant locality of 

 the blue fossiliferous limestone. 



At s, on both sides of the channel, the upper surface of the 

 stratified rock is evidently water-worn. The distance between 

 these two points is one hundred and twenty six feet ; this was 

 probably the usual width of the stream, and agreeably to this 

 supposition the depth of water was about six feet. Water con- 

 stantly issues from between the silt and diluvium, and trickles 

 down the sloping surface b, which it has whitened with a calca- 

 reous incrustation. Laborers in the vicinity have excavated little 

 pouches at the junction of the diluvium and silt, and by this 

 means they procure sufficient water to quench their thirst ; the 

 pedestrian also not unfrequently turns aside here for a refreshing 

 draught. Whitewater River, near Richmond, at times becomes 

 a formidable current ; but in the driest seasons of the year, the 

 quantity of water flowing in its channel has been estimated to 

 be barely sufficient to supply a canal, so that it can hardly be 

 questioned that the now buried channel once conveyed at least 

 as much water as our present river. As the silt on the other side 

 of the road is comparatively dry, the plausible supposition is, that 

 the stream flowed to the south. 



In the silt, removed for the passage of the national road, sticks 

 and other vegetable matter were found ; and in portions of this 

 fluviatile deposit which I have examined, I have detected at 

 various times, small soggy pieces of wood, such as we find at 



