My family has had one just like this in our family for about 200 years. It has had 4 new heads and 6 new handles but is still in fine shape today.
The notch...that is for pulling and bending nails? My dad had one too.Have one too, didn't know that was the purpose.
My Dad used to make us these little flat arrows made from wood shakes. I always wondered how he got so good with that hatchet. He would whittle out about 10 arrows and a 18" long stick and then he would tie a string to the stick. We would fling the arrows up in the air and see how long it would take for them to come down. Great fun.My understanding is the hatchet part is for splitting the shakes, the hammer head is obvious and the notch is the nail puller.