I am amazed at how good the data usually is for the U.S. soil surveys. Those people did an excellent job of projecting the actual distribution of soils from limited sampling.
However, they did not dig test holes on your land, so their "depth to bedrock" numbers are general estimates. I agree with your excellent idea to dig some test holes!
Your 41% clay content is certainly good news. That is typically sufficient to provide a pond seal. With good clay you have the ability to excavate part of your pond depth AND build an embankment to impound even more water. Basically, if you have a good pond location that is 6' to bedrock, you can excavate to rock, backfill with a 1' deep clay blanket, and then build a dam that is 5' above the original ground level to create a pond that is 10' deep.
