UPDATE: Derek’s got much more information on the CJ-3B site.

This image was on Vulcanhammer.net, but no longer seems to be there. In it, you can see Raymond Concrete Pile Company’s Gow Division’s SPT rig using a PTO to bore a hole for soil research.  This is actually an advertisement for the Jeep.

The caption with the image is, “The Jeep helps cut our costs by getting more done”.

And the text below the image is:
In building anything big, the first step is soil sampling.  Gow Division of the Raymond Concrete Pile Company.  57-year-old construction company with projects around the world, keeps its 28 ‘Jeeps’ going eight hours a day in its work of investigating soil conditions to furnish information to architects and designers so they can determine the best type of foundations for construction projects of all kinds.  Here is one of Raymond’s “Jeeps” with power take-off being used to operate an exploratory boring outfit.

The manager of Raymond’s Gow Boring division says: “We were the first to use the “Jeep” in soil testing work, and we have been using more and more “Jeeps” ever since.  The “Jeep” helps cut our costs by getting more done. It can maneuver over rough ground in the country and get into tight spots between buildings in the city.  It furnishes the pwoer for operationg our rigs and carries our equipment quickly from job to job so that we’re always ready to go.”

Here’s an example of a post hole digger. So, maybe they ‘dig’ with some kind of custom corer and then use the PTO to lift it (which is what they appear to be doing in the photo above)?