scramble or scumble?

[Wolfe, Skip]

>> all got scrambled together, eventually, by the knives of the seasons,
             ^^^^^^^^^
>> to an impasto, feet thick, of unbelievable black topsoil in which
>> anything could grow, not the least being bananas."

>I confess not to having a copy of GR at hand, but isn't it
>"scumbled"? I remember being struck by the word on all my previous
>readings. Apparently it's an archaic word for shit.

You're right about the word being "scumbled."  It's actually an artists' 
word -- I think it means to mix up or dilute colors or something like that. 
 It and "impasto" are part of the same metaphor here.