1872. ] 59 (Perry. 
traverse. Pot-holes, which are generally supposed to have been 
eroded by torrential streams, likewise occur in peculiar positions 
and at various heichts; they are found far up the sides and near the 
tops of mountains, along which, so far as one can now judge, no 
ordinary river ever flowed. 
(2.) The planation of the subjacent rocks. Long-continued ex- 
amination of the surface of the solid frame-work of the country, as 
it has been gradually uncovered by natural processes, or from time 
to time laid bare artificially, both in the State of New York and in 
each of the New England States, to say nothing of other parts of 
the country, clearly shows that such surfaces have been not only 
eroded, but also smoothed in a striking manner. The great extent 
to which this smoothing prevails over all newly-bared rocks, also 
sugeests that probably the superficial area of almost the whole 
region has undergone a peculiar kind of planing. Indeed, rocks 
nearly everywhere, when freshly uncovered, disclose a characteristic 
sort of polishing. And they have been thus smoothed, not by the 
usual action of aerial agencies, and not by water in its accustomed 
modes of working. All this is manifest on the close inspection of 
these surfaces, especially when they are compared with those which 
have been subjected to various other influences. Nearly every 
ledge, if examined when the soil is just removed, is seen to have 
been worn down, smoothed and polished, as if with emery — polished 
in a manner seldom to be mistaken, particularly if concomitants be 
brought into account by such as have become familiar with the dis- 
tinctive features of this planation. The reason that the surface of 
so many solid rocks fails to exhibit the results of this process, is 
found in the fact that continued exposure to the elements has led to 
their effacement. But even on the face of rocks long weathered, 
the practiced eye will often detect abundant traces of this peculiar 
character. No one, it is confidently believed, can attentively ob- 
serve the evidence on this point, and not be amazed at its extent. 
(3.) The striation of the subjacent rocks. This is likewise very 
evident. Almost every recently exposed surface of underlying rock 
reveals furrows, grooves and scratches of a distinctive kind. They 
have characters which seldom need to be mistaken, and which 
usually render their recognition easy. Ordinarily they are in 
straight lines, and those of the same series are, in the main, parallel, 
while such as belong to different sets are often seen to cross each 
other at greatly varying angles. These markings are also of a 
