INITIAL INVESTIGATIONS Its interest aroused, Amprex's Exploration 

 OF THE ARENOSO BASIN Department assigned two experienced geolo- 



gists to investigate the region. Utilizing the 

 company's geology library and its staff, the geologists made an intensive search 

 for all available published and unpublished information pertaining not only to 

 the Arenoso Basin but also to the surrounding area for hundreds of miles in 

 order to develop the regional pattern of geology which might afford better 

 understanding of local conditions. At the same time that the literature stage of 

 investigation was initiated, the Exploration Department requested that Amprex's 

 Law Department begin investigating the legal problems that would be inherent 

 in operating in the Arenoso Basin. The Land Section of the Exploration De- 

 partment was asked to make a land check of the area and ascertain what prob- 

 lems would confront them in acquisition of leases. The Scouting Section of the 

 Exploration Department was instructed to search all sources for data relating 

 to the area and, particuarly, if at all possible, to locate a set of cuttings and cores 

 from the two wildcat wells. Federal and state geological surveys, universities and 

 colleges, federal and state ground-water districts, and all other agencies that 

 might have information pertaining to the area were contacted. All of this data 

 gathering was conducted with a minimum of publicity. 



As the available data were assembled from various sources, Amprex's two 

 geologists, assisted by a staff of draftsmen and stenographers, began integrating 

 this information into a summary of the regional geology. They constructed 

 regional geological maps. A composite areal geologic map was compiled, utiliz- 

 ing both federal and state mapping. It had been determined that a few local 

 areas had been mapped by graduate students working on thesis problems, and 

 their maps were incorporated into the composite regional map. It was found 

 that a federal agency had "flown" the area, and the aerial photographs were 

 purchased. After a photographic mosaic was constructed from these air-photos, 

 specialists trained in photogeology developed areal geologic and structural maps 

 from studies of the photographs and other available data. From the few meas- 

 ured geologic sections exposed in the mountains, hills, and canyons of the 

 region, Amprex's geologists constructed preliminary regional thickness and 

 facies maps of the sedimentary rocks and made preliminary paleogeographic 

 and paleogeologic interpretations. 



After compiling and studying the available information, Amprex's geologists 

 moved into the field and began reconnaissance geological studies of the surface 

 outcrops. Utilizing the assistance of highly trained specialists of the company's 

 Geologic Research Section, these geologists measured and described in detail 

 geologic sections that outcropped in different parts of the hills and mountains 

 surrounding the alluvial floor of the basin. These sections provided a key to 

 the subsurface stratigraphy of the valley. 



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