For Westpoint Hill, I reckon they they had two different...

For Westpoint Hill, I reckon they they had two different sampling processes in play. Firstly, they would have been out equip with their fancy quad bikes and hand auger's sampling the top of hard calcrete and getting lots of blisters. Then, when they got some interesting results, they sent in the big guns, probably a Toyota mounted mechanical auger. This would have been able to punch through the hard pan and got samples from a deeper horizon in the soil/calcrete profile. Don't need Dr Wills to realise it's like assaying apples and oranges. Calcrete sampling still has elements of unknowns. If you dig down into it (pardon the pun), I think Challeneger was actually sticking out the ground........
Interested to hear other view points on this.
My advice is that when you are running any sampling program, it is imperative that the methodology it's kept consistent.