WHAT'S IN A NAME? BARNUM BROWN'S HELL CREEK LOCATION AND HELL CREEK FORMATION OBSERVATIONS

In the field, a geologist uses whatever map is available. Time passes. Scientists revisit the same area and assume the names of features have remained the same, which is not always the case. Barnum Brown named the Hell Creek Formation in 1907 for exposures on Hell Creek and its tributaries in northeast Montana. Brown and others worked the strata cropping out along this drainage in the early 1900s and may have identified the tributaries of the Hell Creek differently than labeled on maps used today. Brown used a hand-drawn map by Hornaday (1902) to reach Hell Creek. Although distorted, Brown’s published map does reflect current usage. Brown references, however, a S-to-N flow on a more professionally drawn map by his colleague Leonard (1907), in a footnoted reference to Cameron’s (1907) map, and by his notations on unpublished information. Other than our thinking that these 1907 "Dawson" County maps were only of limited detail, one can note the Bureau of Land Management General Land Office Records township plat maps surveyed in 1911 and published in 1913 labeled the current Ried Coulee and current main branch of Hell Creek downstream from Ried Coulee as "East Fork Hell Creek." "East Fork," upstream of the streams' confluence, was later renamed Ried Coulee, and the longer branch retained the current map name of Hell Creek. This current use is similar to that found on township plats surveyed in 1914 by a Dawson County surveyor (Garfield County Clerk and Records). Using Leonard’s field notes, we know he joined Brown in the field in 1906 on the "East Fork Hell Creek." Brown provided a summary of his geological observations to date and Leonard offered formational thicknesses determined with his effectively used barometer. Leonard also described the only complete Pierre to Fort Union geologic section, which traversed the East Fork of Hell Creek. Recognition of where specific geologic observations were made in the original work on the Hell Creek Formation is both of historic interest and of importance to examining and evaluating the original intent of the author and correlation of strata in the vicinity of the type locality. Reevaluating the geologic sections by the naming authors is a time honored and valuable exercise in documenting the history of the Hell Creek Formation.