Turns out the most useful tool was a hatchet that we had brought back from Clovis when we cleared out her grandfather's estate earlier that year. The roots were so thick that I could not dig through them with a shovel. I literally cut a perimeter with the hatchet for each set of blocks and pulled it out as a near solid plug. We had been studying how to level and square the foundation and found it was more difficult to get the batter boards lined up properly than it was to level the piers. Once
Once all of the piers were in place and level and square, we built a frame of beams, a stud inside of a track. Still only a 2x4 in dimension but incredibly strong. I decided afterwards that we could have done with fewer piers but I wasn't about to take any out after the battle to get them into place! :)
Detail of the corners of the beams. We cut and overlapped the ends of the steel and then put a corner bracket in for extra measure. 2x6 16 gauge nested together and screwed securely every couple of feet. This easily would have held the 2 story structure that we had originally planned.