I have been going through a lot of census records lately from 1810 up to 1950. I have noticed some notations probably written in by the census taker appearing in the 1940 census. I understand that a circle with an X signifies the person that gave information to the census taker but have also noticed a check mark that looks like it was put there by the census taker and then later circled by someone else? So far, I have only seen it next to infants less that a year old, but there has to be some significance there. Just curious.