Geophysical Investigation of the Montana Lineament

A zone of aligned geologic features extends intermittently from the Pacific coast of northwestern United States eastv/ard into the Great Plains. It can be recognized on geologic and tectonic maps of North America (Goddard et al., 1969; King, 1969) as a structural zone through Washington, northern Idaho, and Montana. The zone is defined by a diverse collection of geologic elements, although at present, evidence for the zone is largely physiographic over much of its extent. Various segments have been recognized by authors of general works on North American geology (Eardley, 1951; King, 1959# Badgley, 1965). In total, the geologic evolution and structural motif remain poorly understood. Even the location of regional segments of 320 km in length will vary according to the criteria used for definition (Weidman, 1965). The farthest recognized projection of this lineament to the southeast includes an offset of the Mid-Continent gravity high in Iowa (Sales, 1968). -- Introduction, paragraph 1 Note that 5 maps were included with the physical copy of the thesis. They will be available as digital files with this digital record once they have been scanned