Stonemason terminology - "Turtle"

A day in the making, "turtles" are conceived when your mason mixes a fresh batch of mortar and goes to have "just one beer." They are born when he returns the next day with a hang-over and dumps out his wheel-barrow. The stonemasons told me about one of their peers who was notorious for his turtles. Legend has it, he left two dozen turtles on one brick job before the work was complete. Amusing if the mason's are buying the cement and sand, not so amusing if you're buying it! So far, after 50+ bags of cement and about 8 tons of sand, we have only two turtles on our job site. Not bad... as you can see, our clay soil could use some lime and sand amendments.

And to think, I thought a turtle was a roofer's term - as in when you stay on the roof too long before going to the outhouse.