Through Cass County north of Logansport spans part of a buried prehistoric river valley that stretches across four states.
Starting in present-day West Virginia, the Teays River once flowed northwest into what's currently Ohio and through Indiana before joining the ancestral Mississippi River in Illinois. While the valley lies in places up to hundreds of feet underground, water still makes its way through the ancient channel.
A 2003 report from the Indiana Department of Natural Resources describes the Teays River Valley as a drainage system whose headwaters started in present-day North Carolina before running north into what's currently Virginia and on into West Virginia.
"It was a massive watershed in mid-western North America," said Jim Jackson, manager of water, wastewater and stormwater for Logansport Municipal Utilities.
Walter Sullivan reported in The New York Times in 1983 that geologist William G. Tight discovered and named the river valley after the village of Teays in West Virginia in 1903.
The DNR report refers to the Teays River Valley through north-central Indiana as the Lafayette (Teays) Bedrock Valley to recognize "the importance of the various major tributaries to the Teays."
Beginning in Adams County on Indiana's border with Ohio, the DNR report states the valley heads west through a total of 11 counties and about 165 miles, leaving the state through Benton County and continuing into Illinois.
In east-central Indiana, the report states that the valley is a mile wide or less while in other locations like Lafayette, it broadens to a width of several miles.
The river reached maturity in the late Tertiary Period, according to "The Mysterious Teays River," an article by Michael W. Gos available at the Cass County Historical Society. Merriam-Webster's dictionary defines the Tertiary Period as the first period of the Cenozoic Era, which began 66 million years ago after the extinction of dinosaurs.
Eventually glaciers descended south toward the river, pushing sand, gravel, silt and other materials of varying texture and thickness, according to the DNR report.
"With few exceptions, evidence of this once extensive drainage system is now obliterated by thick deposits of glacial materials," the report states.
Jackson described the glaciers as acting like an enormous bulldozer moving across the land and pushing dirt into the river — a bulldozer that moves about a half-inch a year over a long period of time.
Materials filling the Lafayette (Teays) Bedrock Valley range between 200 to 425 feet thick, with a typical thickness of more than 300 feet, according to the DNR report.
"In none of the test holes drilled for this project was there any indication that the materials filling the valley were anything other than Pleistocene Age," the report states.
The Pleistocene Age began about 1.8 million years ago and lasted until about 11,700 years ago.
"Its presence and location is only defined by available records of oil and gas wells ... test holes, water wells and seismic data, except in some circumstances such as at Richvalley-Peru where the present valley of the Wabash River reflects the modifications by the buried bedrock valley," according to the DNR report.
Gos' article describes the Wabash River as partially exhuming the Teays River valley in this area, where "the Wabash valley broadens and is lined with till bluffs."
"The presence of a major buried valley in Indiana was first discovered in a heavily glaciated area in the northeast part of the state" in the early 1890s during the drilling of oil fields, Gos wrote.
The DNR report also describes the Teays as "[l]ong regarded by area residents as an 'underground river'" and sets out to dispel that notion.
"...[W]ater in the valley is not part of an underground river," the report states. "The water present is found within granular deposits of sand and gravel. The movement of the water within these deposits is only a slow trickle, generally at the rate of movement of less than five feet per day. Also, the valley is not a discharge point for the regional groundwater as some believe, nor does ground water flow down the valley like a river as has been suggested."
Jackson said communities along the underground valley's path draw their water from it, as do residential wells. LMU explored it as a possibility but was hesitant to go about 2 miles north of town to do so, Jackson continued, adding water in the underground valley tends to have high iron levels.
The part of the river valley from near Peru to near Logansport is about 450 feet below sea level and about a mile and a half wide, according to the DNR report, which adds part of it spans beneath the Eel River.
Between near Logansport and near Lake Cicott, its width is about 2 miles, the report continues. Part of this stretch revealed "the presence of sizable amounts of wood" that carbon dating placed at over 21,500 years old, according to the report.