Bituminization of Wood. 119 



the level of high water of the Mississippi, may be seen a shelf 

 extending some distance into the river. The level surface of this 

 projecting shelf was covered by earth which had fallen from the 

 bluff, forming a kind of talus x. This superincumbent mass of 

 earth was removed in forming a new steam boat landing, and a 

 surface was exposed, covered with logs partly changed into a 

 glossy black coal, and with many stumps standing erect where 

 they had evidently grown. The logs and branches found on 

 this surface were very much flattened, some portions of them be- 

 ing very soft, while the remainder was in various degrees bitu- 

 minized. Many bore the marks of the axe so distinct as to be 

 recognized without hesitation by all who examined them. This 

 circumstance misled me, and induced me to consider the deposit 

 as much more recent than, as will be hereafter seen, it really is. 

 The axe marks must of course be, comparatively recent, though 

 they were evidently made before the change in the wood com- 

 menced. From the data obtained during my first hasty and su- 

 perficial examination, I concluded, that the deposit was a small 

 one, formed by the Mississippi, and resting against the clay of the 

 bluff, which I supposed to present a face somewhat similar to the 

 line, w y. 



I was led to give the locacity a more careful examination, from 

 being told by those who had been long acquainted with the place, 

 that the bluff had within their recollection, retreated very consid- 

 erably, and in fact, a field which is said to have extended more 

 than four hundred yards back from the edge of the bluff, has 

 almost disappeared, by falling into the river beneath, which is 

 evidently encroaching rapidly at this time in consequence of a 

 strong current setting against the bank at this point, situated as it 

 is in the lower part of a considerable bend, which the river makes 

 here. 



I will now proceed to give, in a manner as condensed as pos- 

 sible, a statement of the result of a more thorough examin- 

 ation. 



Figure 2, represents a section of the bluff. 



No. 1. A layer of reddish sandy clay which forms the sub-soil 

 in this region. 



No 2. A bed of sand of variable thickness, in which water is 

 obtained, by sinking wells to it in various parts of the adjoining 

 county. It often contains, and sometimes lies between beds of 



