While researching my wife's side, I ran into a bit of a stumbling block. Her great-grandmother was known as "Mary Tusk". I ordered the records from the church they attended in Buffalo, New York (Saint Stanislaus). The records were in Latin, but the spellings of the family names were all recorded by a Polish speaker. Very long names....
The "Tusk" name that Mary adopted was actually a shortening of her mother's maiden name. I'm not sure why whe did this, but her father's name was Michael Jerrewski, and she was baptized as Marya Jerrewska. I have looked through the records pretty well, and the name is consistently spelled "Jerrewski and Jerrewska". The records that I viewed covered the late 1800s and the early 1900s. In the census, and in modern records, the family name is "Jezewski".
I hope that this information will help someone...
Steve Macko