I have a book, copyright 1883 and 1901, entitlie "Library of Wit and Humor" by Eli Perkins and Others. The cover of the book has a photo of Samuel Clemens who, of course, wrote under the pen name of Mark Twain. On the inside is a sketch of Melville D. Landon who wrote under the pen name of Eli Perkins. The "Many Others" includes Josh Billings (who was initially promoted by Eli Perkins), Bret Harte, and Eugene Field. Josh Billings, who's real name was Henry Wheeler Shaw, was probably the second most popular humorist, lecturer, and writer in the US in the latter 1800s.

On page 87 of the book is found a short piece entitled, "Very Closely Related" that goes like this:

"Well, Sam, I'll tell you how it is. You see, I married a widow, and this widow had a daughter. Then my father, being a widower, married our daughter so you see my father is my own son-in-law."

"Yes, I see."

"Then again my step-daughter is my step-mother, ain't she? Well, then, her mother is my grandmother, ain't she? I am married to her, ain't I? So that makes me my own grandfather, doesn't it?"

Many of the writings in this book are credited specifically to one or another of the contributors, but quite a few are not. The "Very Closely Related" piece is one of the ones that is not. If this book is the one the song idea came from, it's as likely that Eli Perkins wrote the own-Grandpa thing a Mark Twain. It does sound very much like Mark Twain's style, but I think it sounds more like Eli Perkins. Also, the last writer credited before this piece was Eli Perkins. It's impossible to tell for sure from this volume who actually authored the piece. Of course the source could have been a different book altogether.

This gives me an idea for a funny song about 19th humorists with pen names that wrote alike--maybe a guy named Arthur who's his own author. No, that's lame--hafta work on that.