This is a detached garage for a home built in 1912.
I’m not sure what to call these blocks. They are hollow and seem like a ceramic material.
Anybody know what they are?
Although I’ve never seen that design on the outside, they look like “glazed” structural terra cotta block: http://www.oldhouseweb.com/how-to-advice/structural-terra-cotta.shtml
Larry has it, clay terra cotta foundation blocks.
What’d you do, hit it with a hammer? 
Haven’t seen those in awhile
lol. There were several of these holes in the garage. Huge set of pull down oak stairs to an upstairs storage area. They had a 10"x8" counter weight and pulley system. I wasn’t strong enough to push that little weight up to allow the right side of the steps to touch the floor! and the exterior person door was “self closing” with a weight and pulley system as well.
People in that ere were innovative indeed!
It seems more and more people are losing creativity for sure 