Author Profile

Eric Clausen

At present I am a professor emeritus having taught geology at Minot State University (North Dakota, USA) from 1968 until 1997. I was trained in geology at Columbia University and the University of Wyoming where my studies emphasized regional geomorphology. For many years I have pursued a research interest that developed when as result of geologic field work and interpretation of large mosaics of detailed North American topographic maps I discovered significant evidence previous investigators had ignored. Over a period of many years, after studying such anomalous evidence, I was forced to develop a fundamentally different interpretation of North American geomorphic history than that which is generally accepted. Geomorphology is the study of landforms and my interest as a geomorphology researcher is in determining the origin of large drainage systems, such as the Missouri River drainage basin in North America. The Missouri River drainage basin consists of thousands of smaller drainage basins, each of which has a history my essays (website posts) are trying to unravel. What I try to do is reconstruct the landscape the way it looked prior to the present day drainage system. I then try to determine how the present day drainage system evolved. While conducting my Missouri River drainage basin landform origins study I also developed an interest in scientific paradigms, especially in how scientific paradigms develop and how they are replaced. The Missouri River drainage basin landform origins project at has been completed and I am currently creating a catalog of Philadelphia, PA area erosional landforms, which can be found at For off site questions and discussions about either project I can be contacted at

Recent Posts

The Topographic Map Mystery: Geology’s Unrecognized Paradigm Problem

“The Topographic Map Mystery: Geology’s Unrecognized Paradigm Problem” is a new book published in January of 2023 that discusses why the geology research community’s Cenozoic geology and glacial history paradigm cannot explain most topographic map drainage system and erosional landform evidence (such as the topographic map evidence described on the website) and describing a new […]

Published papers related to this Philadelphia area landform origins website

Papers related to this Philadelphia area landform origins website that have been published to date are listed below. Links are given for abstracts and full text pdf copies as noted. Full texts for articles published in The Pennsylvania Geographer can be obtained by contacting the author. Additional papers may be added when available. —, 2015, Exploring […]

Erosional History of the Sandy Run Drainage basin, Montgomery County, Pennsylvania

Introduction: Sandy Run is an interesting secondary drainage route as it drains the Chester Valley east end (also known as the Roslyn Valley) in a west-southwest direction, but instead of continuing a short distance further on the Chester Valley floor to join south oriented Wissahickon Creek, it turns in a north direction to flow through […]

The Brandywine Creek-Red Clay Creek divide area near Longwood Gardens

Longwood Gardens near Kennett Square in Chester County is located on the drainage divide between Brandywine Creek to the east and Red Clay Creek to the west. A former east-to-west oriented water flow channel crosses the present-day Brandywine Creek-Red Clay Creek divide on the Longwood Gardens grounds on the north side of the main conservatory […]

Bucks County through valley inventory by township

This inventory is an effort to identify each township’s most prominent through valley, or through valleys and many less prominent through valleys are not included. The through valleys provide evidence of former drainage routes that can best be explained in the context of massive and prolonged southwest oriented floods that were sequentially captured by headward […]

Guide to Landforms Seen Along SEPTA’s Lansdale-Doylestown Regional Rail Line

Overview: Along its 34.4-mile trip from Center City Philadelphia to Doylestown a SEPTA train travels from the Philadelphia City Center to and then along the Coastal Plain-Piedmont Province boundary before moving from the Coastal Plain onto the Piedmont to reach the Tookany Creek drainage basin. Once in the Tookany Creek valley the train travels in […]

Guide to Landforms Seen Along SEPTA’s West Trenton Regional Rail Line

Overview: Along its 32.5-mile trip from Center City Philadelphia to West Trenton a SEPTA West Trenton train travels from the Philadelphia City Center to and then along the Coastal Plain-Piedmont boundary before moving onto the Piedmont Province to reach the Tookany Creek drainage basin. Once in the Tookany Creek valley the train travels in a […]

Millstone River water gap near Princeton, NJ

An interesting New Jersey landform providing significant information related to Philadelphia area landforms is the Millstone River water gap located near Princeton. The Millstone River flows in a northwest direction, as seen at location 1 in figure 1, to enter Carnegie Lake at Princeton and then to flow in a north direction to location 2. […]

Some reasons why previous researchers have been unable to explain Pennsylvania drainage route origins

While speculation about Pennsylvania drainage route origins and more specifically water and wind gap origins can be traced back to the early 1700s the questions still persist and the speculation continues[1] This inability of researchers to explain Pennsylvania drainage features, such as the large-scale Susquehanna River and Delaware River water gaps, is puzzling as similar […]

Chester Valley Origin: Some Alternate Interpretations

To date this website has used simple map interpretation methods when interpreting Philadelphia area landform origins and previous researcher interpretations have not been mentioned. While multiple Philadelphia area geologic and geographic studies have been conducted over the past 150 years origins of most landforms interpreted here have never been addressed at least in a way […]

Through Valley Crossing the Delaware-Schuylkill Drainage Divide at Deer Run and East Branch Perkiomen Creek

A well defined northeast-to-southwest oriented through valley links the northwest oriented Deer Run valley with the southwest oriented East Branch Perkiomen Creek valley. The Deer Run valley drains to southeast, east, and south oriented Tohickon Creek, which flows to the southeast oriented Delaware River and the East Branch Perkiomen Creek drains to south and southwest […]

Morris Run: An East Branch Perkiomen Creek Barbed Tributary

Morris Run is an East Branch Perkiomen Creek tributary located between Perkasie and Dublin in Bucks County and originates as a northeast oriented stream before turning in north, west, north, and northwest directions to join southwest oriented East Branch Perkiomen Creek. Most Morris Run tributaries flow in southwest directions to join north oriented Morris Run […]

Evidence of Diverging and Converging Channels in the Souderton-Telford Region

Shallow wind gaps in Souderton and Telford area link headwaters of northeast and southwest oriented Perkiomen Creek tributaries and provide evidence of what were diverging and converging flood flow channels. Evidence of former channels include the present day southwest oriented East Branch Perkiomen Creek valley, a shallow wind gap in Telford linking a northeast oriented […]

Schuylkill River Elbows of Capture Upstream from Valley Forge National Historical Park

The Schuylkill River between Phoenixville and Norristown makes several remarkable direction changes including two complete U-turns just upstream from Valley Forge National Historical Park. Other interesting Schuylkill River U-turns or perhaps incised meanders are found between Pottstown and Phoenixville, although this essay will focus on the U-turns between Phoenixville and Valley Forge National Historical Park. […]

The Chester Valley Drainage Divide between the Delaware and Schuylkill River

The Chester Valley is a narrow lowland extending from near the southeast oriented Susquehanna River valley in an east-northeast direction almost to the southeast oriented Schuylkill River valley. The Pennsylvania Geologic Survey web applications map shows the Chester Valley to be underlain by easily eroded carbonate rocks. The Chester Valley north rim (North Valley Hills) […]

Water and Wind Gaps near Christiana, Pennsylvania

Christiana is a small community located about 50 miles west of Philadelphia and just north of a water gap where East Branch Octoraro Creek headwaters cross the North Valley Hills. South of that water gap the East Branch Octoraro Creek flows across the east-northeast oriented Chester Valley and then flows through another water gap as […]