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make this method unreliable for absolute determination of hardness it has nevertheless been possible to check the method from time to time with cores and occasional cuttings and has been found to reflect with reasonable consistency the true relative hardness. However, on the basis of drilling-time records and rate of penetration of the core barrel at the greater depth (3000'± and deeper) it was feared, prior to actual recovery of core [[11??]], that because the drill penetrated the rock [[strikethrough]] sof [[/strikethrough]] so easily, (fast and smooth) there was [[strikethrough]] als [[/strikethrough]] very soft ^[[i.e. chalky or unconsolidated]] rock at this interval (4197-4222) and core recovery would be negligible. The core recovered proved this assumption false. Recovery was 44% and the rock is "fairly hard." There has, in fact, been ^[[detected]] a tendency to under estimate the hardness of the last two cores (9 & 10) before actual recovery. In the case of core 11, at least, there are two possible explanations for this (or a combination of the two) 1) The greater length of the drill pipe and its greater weight would have a

[[circled]] 10 [[/circled]]