Maps. Oklahoma. Maps of northeastern Oklahoma and parts of adjacent States showing thickness and subsurface distribution of Lower Ordovician and Upper Cambrian rocks below Stimpson group, maps also show oil and gas pools in these rocks, by H. Andrew Ireland, assisted by John H. Warren; oil and gas vestigations, preliminary map 52 [with text] by H. Andrew Ireland. Scale 10 in. =1.3 in. n. p.