Hi Carol,
Here's the rest of what I found out
I doubled checked the marriage indexes for Alexander Longmuir & Eleanor Heron's marriage and there isn't one listed between 1853-1889. After 1889 the indexes are on micro-film and I didn't have the time to check those years.
The closest record I found, was
Ellen Heron marrying Joseph Fink on 28 Feb 1882 - book 82 page 638
The marriage records at the Rhode Island archives are cross-indexed. There is a Bride Index and a Groom Index. I checked both, just in case something was missed.
In the Bride Marriage Index 1853-1878, there were two female "Heron" married. One was named Catherine Heron and she married Michael O'Neil, on 30 Sept 1855 in Providence, Rhode Island. Their birthplace is listed as Ireland and no parents names are noted.
I can't read the other "Heron" female's last name on the marriage record. Ken slipped off to lunch while I was there and another clerk helped me and took the piece of paper that I had her named written down on.

So I have the record and maybe you can figure out who she is?

I'm not very good at reading bad hand-writing, poor eyesight. I'm totally unsure if ither of these two ladies are connected to Eleanor's family, but I picked them up just in case?
Bride Marriage Index 1853-1878
Catherine Heron
Female Heron
No listing for an Eleanor Heron marrying Alexander Longmuir or Longmore
Groom Marriage Index 1853-1878 as follows
Long
Longe
LongKing
Longley
Longstreet
Longworth
Longworrthy
................................................................
Bride Marriage Index 1879-1889
Heron Ellen m. Joseph Fink
Groom Marriage Index 1879-1889
Long
Longbottom
Longe
Longfellow
Longley
Lonnegreen
Lonzon
Looby
Loomas
Dogs leave paw prints on your heart.
Maxine Morning b. 23 April 1998 d. 14 Nov. 2008
http://talkingscot.com/gallery/displayimage.php?pos=-1718