June 25, 2004
New Digital Geologic Maps Available for Hole-In-The-Wall Country

The Wyoming State Geological Survey (WSGS) has released the first two of a planned group of 12 digital quadrangle geologic maps for the southern Bighorn Mountains. Map author Alan Ver Ploeg, Senior Geologist and Head of the Geologic Mapping Section at the WSGS, announced that color geologic maps covering the Hole-in-the-Wall and Poker Butte 1:24,000-scale quadrangles are now available from the WSGS as Open File Reports (OFRs) 04-12 and 04-13, respectively. Preliminary versions of the maps were released in 1998 as blackline copies; the maps have since been revised and digitized. Each map includes a geologic cross section to illustrate the structure present in the area.

Ver Ploeg notes that interest in the hydrogeology and minerals in the area prompted the completion of these maps. Over the past several years, the WSGS has received requests for information on the general geology and structure of the area to aid in the siting of water wells in the vicinity of local ranches. Bentonite is mined from the Frontier Formation which crops out in the northeastern corner of the Hole-in-the-Wall Quadrangle and potential exists to extend these mines to the west and south along trends shown on the map. In addition, there are numerous terrace deposits mapped on both quadrangles, which could serve as a local source for sand and gravel.

The geographic feature known as Hole-in-the-Wall occurs on the quadrangle by the same name. The Hole-in-the-Wall is a narrow notch eroded in a nearly continuous, vertical cliff of Triassic Chugwater Formation, locally referred to as the ÒRed Wall.Ó This significant topographic feature runs for almost 25 miles north to south along the east slope of the southern Bighorn Mountains. The Hole-in-the-Wall and the area around it was made famous by various groups of outlaws, rustlers, and army deserters who used this erosional feature as a hidden route in and out of the rugged surrounding area, which served as a hideout for many years. Probably the most notable of the outlaws were Butch Cassidy and the Sundance Kid, with their famous Hole-in-the-Wall gang.

The maps can be purchased over the counter of by phone, fax, or Email from the Publications Sales Office at the WSGS in Laramie. Each map sells for $10.00 each, available as a color plotted map, rolled only. The digital coverage, in the form of GIS shape files (created in ESRI¨ ArcInfo¨) along with the metadata files will be available in the near future.

Press Release
from the Office of the Wyoming State Geologist
Ron Surdam, State Geologist