The Zwolle plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
Zwolle’s center stands about 200 ft above sea level. Within three miles the land runs from 160 ft to 330 ft, a difference of 170 ft: gently rolling country.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sand, clay, lignite. Age: Paleocene, 56 to 66 million years old. About 9 mi of the line.
Clay. Age: Holocene, less than 12,000 years old. About 6 mi of the line.
Clay, silt, sand. Age: Pleistocene, less than 2.6 million years old. About 4 mi of the line.
Mudstone. Age: Late Paleocene to Early Eocene, 48 to 59 million years old. About 0.3 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Zwolle reaches the Gulf of America by way of the Bayou Scie and the Sabine: about 210 river miles.
Lakes on the way: Toledo Bend Reservoir and Sabine Lake.
140 miles of the trip are on the Sabine.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Zwolle; river miles along the main stem, rounded.