So dig a good sized soil pit or planting site and ID your soil or have a local agrologist help out.
Sampling can be on a grid of several hundred feet to several miles apart. Even looking on a soils map of a soil survey doesn't tell the whole story, as there are many inclusions (or other soil types) on that sampled area which may not be mapped. Sure helps to know your soil type to give a proper diagnoses though. Just think of it as an excerpt (snippet) from a soils survey report of your state, and there are other types of soils to consider, to aid a proper diagnoses.
I think the remarks concerning clay soils was a possible diagnoses for that soil type and not a suggestion that the site was actually composed of clay soil.
