It will be helpful to know the soil types in the subject areas. Your NRCS office can provide soil maps. Along with soil types, and more importantly, they have should have all the detailed mechanical and organic properties of those specific soils. Yes, the soil maps were sampled many years ago and are only to a depth of 5' max, but they will be a good starting source. Another good source that I have used is the state DNR well drilling information. If there are established homes with wells in the area, there will be drilling information detailing the types of soils encountered during drilling (ie; clay, sand, gravel, etc). I don't know if the TX DNR offers this info on-line or not; some of the midwest states do. The Ag. soils maps and tech. info are also sometimes within the official State website, usually buried somewhere in the DNR or USDA section.
