So back in the day before mechanized earth moving equipment construction was done by hand with small tools and shovels. While excavating for our new basement/crawl space we revealed the fine construction of the 1800's!
There is no mortar to speak of between these rocks, it is all dirt. Pretty scary considering we need a 4' opening into this wall to access the current basement and install mechanicals.
It has been standing for close to 200 years!