Fracture patterns, revealed by statistical plots, are markedly different in basement rocks when compared with those in the adjacent sedimentary rock cover. It is suggested that the 400-1,000 feet of basal incompetent Paleozoic rocks acted as an insulator with the result that the higher competent cover rocks acted independently of the basement. Basement foliation is largely discordant with the over-all trend of the range and cannot be correlated with any single fracture direction. The structure of the range formed in response to post-Precambrian regional stresses.

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