I am also a Gerard descendant.I'm afraid we just have to deal with the variances in spellings while doing genealogy. There are many reasons how the spellings of names changed. One of the most common was due to the fact that often people years ago could neither read nor write. So when they gave their name to a minister, public official or census taker, the person taking the information just spelled it the way it sounded to them.Even teachers changed the spelling of family names when children who were too small to speak clearly gave them a name and they wrote down what they thought the child had said. As a result of all of this, we find children in the same family with last names spelled differently. Add to this the many different accents of the immigrants and it amazes you that we can ever piece it all together.
You will find that the French spellings of names can be very hard for those of us who do not speak the language. For example: my grandfather went by the English name of Walter. His French name was Gautier.My advice is if it looks like it might fit, copy it down and look for other clues.Often you will find something else which will finally make that seemingly unmatched piece of info fall right into place.It reminds me of working a jigsaw puzzle. You may pick up a piece several times and examine it before you finally find the spot where it fits. Who knows, we may find that we are working on the same Gerard line.We picked ours up first in Buffalo (believe they came from Quebec). From Buffalo they went to Muskegon, MI and then to Kankakee county, IL and settled in St. Anne.
Good luck to you in your search. It is a barrel of fun but it takes a ton of patience and many years to complete.