That Robert Service opus comes from Ballads of a Cheechako , and from this site.
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Thanks Geoff - I see its by "Howard Weedon". Here's a site about her Maria Howard Weeden (1846-1905) Sounds an interesting lady - here is another banjo song I found by her (from this site). Somewhat questionable lyrics, but here goes:

The Banjo of the Past

By Howard Weeden

YOU ax about dat music made        
On banjos long ago,        
An' wants to know why it ain't played        
By niggers any mo'.        

Dem banjos b'longed to by-gone days               5
When times an' chunes was rare,        
When we was gay as children—'case        
We did n't have a care.        

But when we got our freedom, we        
Found projeckin' was done;               10
Our livin' was to make—you see,        
An' dat lef' out de fun.        

We learned to vote an' read an' spell,        
We learned de taste ob tears—        
An' when you gets dat 'sponsible,               15
De banjo disappears!