Christian, hope you will see this soon and respond. I just found something today which pertains to a MAURER family who immigrated to U.S. arriving about 1888. They were from France but often written as German in Census records. In 1900, the head of household in San Jose, CA was listed as Charles Maurer born 1859. His mother-in-law was listed as Christina BALTZ and there were two young men living with the family surname was KEISER. I recognized all these except the name Charles in this case. However, a French cousin sent me an index to marriages in one village, located in the Alsace region, and a woman of the KEISER name, Catharine was married to a CHRISTIAN JACOB MAURER in 1884. I believe this Christian Jacob was the same person as listed as Charles in the census.
I am now curious if you might be from CA? John V. Reeb