The Butano sandstone formation has been penetrated by 10 modern wells. This principal prospect zone of the Santa Cruz mountain area is a generally impermeable body. More permeable parts of the formation have been located near its top, interbedded with basal parts of the San Lorenzo shale. Stratigraphic and depositional conditions in which the Butano may be a permeable prospect are still present. End_of_Article - Last_Page 187------------
Martin G. McAnd Charles M. Gilbert
P. E. MyerRonald CooperP. H. HaaseCaroine V. Coburn