210 
Dr. Richardson’s Letter on the basaltic Surface 
The same result I apprehend would follow from the opera- 
tions of another agent, which theorists are in the habit of 
calling in to their aid, when they cannot find some certain 
material, which from their theory we had reason to expect ; 
they then tell us it has been carried off', and lost in the suite of 
degradations and decompositions. 
But decay and decomposition, instead of creating inequali- 
ties would produce a contrary effect, and deface those actually 
existing ; they would gradually abate the height of our per- 
pendicular fa9ades, and increase the green steep at their bases 
by the accumulation of the crumbling and mouldering mate- 
rials from above; while the more diminutive fa9ades formed 
by the abruptions of single strata scattered over the face of 
our area, and forming its most characteristic feature, would 
in time ( as many are already ) be converted into steep accli- 
vities covered with verdure. 
Such are the principal causes to which the inequalities of 
our surface have been generally ascribed. Previous to our 
deciding finally upon their insufficiency, it may be proper to 
enumerate a few of those inequalities, where the deviation of 
our present surface, from the form it probably had originally, 
is not only striking, but where also the concomitant circum- 
stances afford demonstration, that some great operation has 
once taken place there. 
Thus, by making ourselves acquainted with effects, we 
shall be better qualified to investigate causes; and if those 
effects shall appear to be beyond the powers of such natural 
agents as we are already acquainted with, we shall be justi- 
fied in admitting the performance of operations to which we 
have seen nothing similar ; and also in admitting the former 
