Home built in 1850 the basement had a brick floor also
The chimney in my mothers house is like that.
These were built this way on purpose, usually a case of the center of the room where the fireplace or wood burning stove sits is not the center of the roof ridge. The mason would start to offset the bricks to line the two up.
That is correct–quite common around here.
You see that inside attics quite a bit as well.
It’s called a brick corbel.
There are corbelling rules including :
a brick shouldnt be corbelled more than 1 inch from the brick below and the total corbelling shouldnt be more than 1/3 of the wall thickness. Those bricks in the pic look to be corbelled more than 1/3 of the wall thickness.