The Lopez 1:24,000-scale detailed reconnaissance surficial geology map (map of unconsolidated materials overlying consolidated bedrock) was produced in four phases. In the first phase, a preliminary surficial deposit map was made using soil mapping (Grubb, 1986), surficial deposit mapping (Denny and Lyford, 1963), bedrock mapping (Sherwood and Platt, 1880; Sevon, 1977), and landform analysis using the 1:24,000-scale topographic map and aerial photographs. In the second phase, the preliminary surficial deposit map was verified and/or corrected during twenty person-days or so of field work. Two undergraduate geologic field assistants, Stephanie Jones and Christopher Guise, were responsible for much of the field mapping. Christopher Guise was responsible for most of southern two-thirds of the map that lies south of Loyalsock Creek, an area largely occupied by State Gamelands. Stephanie Jones was responsible for most of the northern one-third of the map, the area lying north of Loyalsock Creek. Duane Braun, surficial geology mapper, spot checked the work of the field assistants across the entire map and directly mapped the eastern end of the Bernice Coal Basin and the southwestern corner of the map within the Painter Den hunting club lands. In the third phase, the field verified/corrected preliminary surficial geology map was finalized, drafted onto three mylar overlays (contacts, isochores, and labels - rock outcrops), and had a text added by Duane Braun. In the fourth phase, the mylar overlays were scanned, digitized, and produced in Adobe PDF and ArcGIS formats by Pennsylvania Geologic Survey personnel.
The distribution and type of units on the preliminary surficial geology map is primarily a combined parent material and topographic position classification of the soil survey map units. The classification of all soil series by surficial deposit map unit is given in Table 1. Many soil series are common to more than one surficial deposit type. The landform of a specific area is used to decide which surficial deposit type the soil series is most likely related to at that site on the preliminary surficial geology map. The soil series boundaries are manually transferred from the 1:20,000-scale soil survey maps to the 1:24,000-scale topographic map. During the field verification and correction phase many contacts are moved to reflect conditions directly observed in the field. Positions of the boundary lines are estimated by eye using natural and human features that are identifiable on both the soil survey aerial photographs and the topographic map. At some sites a GPS unit was used to better local a contact or feature. Expectable line location error is on the order of 50 to 100 feet on the ground where there are distinct features to guide line placement. Where boundaries cross large featureless areas of forest, line placement error is in the range of 100 feet and occasionally as much as 200 feet on the ground.