A couple of months ago I was able to verify the family branch for Ole and Mari's daughter Iverdine. Iverdine was the twin sister of Bertha that had come to America in 1870 with her sister Rachel.
I also had stumbled upon a few family trees on ancestry.com that were posted by members, though they all had indicated Iverdine's last name was "Finn". Close enough to Finnestad. I then did an internet search and was able to find, based upon the family trees that were posted, the marriage date for Iverdine.
The state of Illinois has a marriage database that is quite helpful, though it doesn't have every marriage, you occasionally will run across something of value.
Because the ancestry.com family tree information provided the name of Iverdine's husband, I was able to verify the date Iverdine and Lewis were married.
This is the information provided on the Illinois marriage database.
Through my research I discovered Dana or Dena is often a shortened version of "Iverdine", and the family tree (referenced above) indicated her husband was "Lewis Joseph Peterson Travland".
TRAVELAND, LOUIS P OLESON, DANA
1872-02-07 D / 1165 LA SALLE
It seemed pretty clear there the information was the same, even if the spellings were different. Louis = Lewis, the "P" obviously for Peterson, Traveland = Travland, Oleson = Olson and Dana = Dena or Iverdine.
LaSalle County is located just southeast of Lee County where many of the Finnestad family eventually settled.
Another piece of information that led me to believe I had the correct wedding data was that Iverdine appeared to have traveled with a Peterson family when she arrived in North America. While Lewis wasn't listed on the same ship, it's probable that the Petersons on the Nordens Dronning were destined to meet up with family members already living in the United States or additional family members were soon to follow.