Thanks, Barb.
As serendipity would have it, I found it a few minutes later while reading Fatout's "Mark Twain on the Lecture Circuit." It is on page 36; it is a prose description of what was on the poster, so it is not verbatim, but gives more info than I had prior, to wit:
A SPLENDID ORCHESTRA is in town, but has not been engaged
A DEN OF FEROCIOUS WILD BEASTS are on exhibit in the next block
A GRAND TORCHLIGHT PROCESSIONMay Be Expected in fact, the public are privileged to expect whatever they choose
- B. Clay Shannon

      From: Barbara Schmidt <[log in to unmask]>
 To: [log in to unmask] 
 Sent: Saturday, November 12, 2016 6:32 AM
 Subject: Re: Has anyone got the text for the Twain lecture poster?
Albert Bigelow Paine's MARK TWAIN: A BIOGRAPHY, p. 292 of the 4-volume
edition (Chapter 54 titled "The Lecturer") features the text and layout of
the poster, although not a reproduction of the poster itself.  The complete
text of Paine's BIOGRAPHY is online at several sites.