In 1870, in addition to the US population census, there is also a mortality census, which lists everyone who died in the 12 months prior to the census. The official census day for 1870 was June 1 and therefore any deaths that occurred between June 1, 1869, and May 31, 1870 should be included. The first line of this list of Dayton residents includes Bridget Gardner, age 15, who died in June, killed by lightning. This implies  a death date of June 1869.

A death by lightning was unusual enough to warrant a mention in the newspaper, and the Ottawa Free Trader printed the following notice on the front page. Clearly this refers to the same young girl listed in the mortality census, whose father was farming some of Mr. Reddick’s land,

HOWEVER, this notice appeared in the Ottawa Free Trader on Saturday, July 2, not in 1869, but in 1870.

It seems most unlikely that the newspaper would save such a notice for a year before publishing it. It is much more likely that Bridget actually died on June 30, 1870. Why, then, does she appear in the mortality census?

When the census taker arrived at the Gardner household on July 21, 1870 and asked his questions, the answers were supposed to be true as of June 1, the official census date. It is very easy, though, to imagine the following interchange:
“Has anyone in your family died in the past year?”
“Yes, my daughter Bridget”
“How old was she and how did she die?
“She was 15 and was struck by lightning.”
“What month did she die in?”
“June”

Actually, Bridget, alive on June 1, should have been listed as a 15-year-old daughter in the family census entry, but adherence to the official census day for information was often overlooked.