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Ernst Cloos papers

Identifier: MS-0124

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Scope and Contents

The Cloos Papers largely document Ernst Cloos's field work and research. The majority of the material deals with the Blue Ridge and Piedmont areas, but there is field material on his early work (1930-1932) in the Sierra Nevadas as well as work on Texas (1955) and Oregon (1957-1958). The materials include his extensive field notebooks in Series 5, his writings in Series 6 which are based on the field work, and his research material and annotated maps in Series 7.

Some of the notebooks, research material and writings relate to Cloos's consulting work. There are notebooks, research and articles for his work for the Thomasville Stone and Lime Company and for the Humble Oil Company (later the Esso Research Production Company) in Oregon, Oklahoma, and Texas. Cloos also did consulting work (1948-64) for the Maryland firm Harry T. Campbell Sons' Corporation. This work was continued by Cloos's colleague Hans Eugster, and except for one report in Series 6, the materials are in Eugster's papers Ms. 209.

Cloos was quite active in the geological profession, but little of this is documented in the collection. Dr. Cloos's wife Margret Spemann Cloos retained his correspondence, and it is likely the professional activities are outlined there. There is a small amount of material on the Geological Society of America (1966, 1968) and the National Academy of Sciences (1963, 1971-73) in Series 3. There are also a few items relating to committee work (1969-70) at Hopkins and a clay workshop (1968) he offered at the University of Georgia.

Cloos succeeded Joseph T. Singewald, Jr. as chairman of the Geology Department in 1952. The one file of Geology Department records which survived in Cloos's papers was correspondence relating to the history of the department compiled by Singewald for President Bowman in the 1940s.

Cloos's papers contain information on three of his colleagues. After Joseph Singewald's death, Cloos prepared "Memorial to Joseph T. Singewald, Jr." (1964). The materials in the Singewald series relate to compiling this memorial. Cloos also prepared a memorial for his close friend Robert Balk. The correspondence relating to this is in Series 1. In addition Balk's wife Christine Lochman-Balk gave Cloos Balk's research papers after Balk's death. These have been removed to form a separate manuscript collection. Cloos also collected material about his brother Hans Cloos. Hans's reprints and letters are in Series 2.


  • Creation: 1921-1980


Conditions Governing Access

This collection is housed off-site and requires 48-hours' notice for retrieval. Please contact Special Collections for more information.

Collection is open for use.

Conditions Governing Use

Single copies may be made for research purposes. Researchers are responsible for determining any copyright questions. It is not necessary to seek our permission as the owner of the physical work to publish or otherwise use public domain materials that we have made available for use, unless Johns Hopkins University holds the copyright.

Biographical / Historical

Ernst Cloos was born May 17, 1898 in Saarbruecken, Germany. He studied biology at the University of Freiburg, but left to study geology at the University of Breslau under his brother Hans Cloos. Ernst received his doctorate in 1923 with a dissertation on the fabric of crystalline rocks of the Bohemian massif.

In the 1920s Cloos worked for Seismos, one of the first companies to apply seismic exploration to the discovery of oil. Cloos worked for them in Texas and Iraq. He returned to the United States in 1930 to do field work on the granitic rocks of the Sierra Nevada. In 1931 Cloos began his lifelong association with The Johns Hopkins University. Hired as a lecturer, Cloos was made associate professor in 1937, and full professor in 1941. He served as chairman of the Geology Department from 1952 until 1963 and retired in 1968.

While at Hopkins, Cloos began his productive study of the crystalline rocks of the Piedmont and Blue Ridge. Most of his important work was based on this study including "Geology of the 'Martic Overthrust' and the Glenarm Series of Pennsylvania and Maryland" with Anna Hietanen (1941); "Oolite Deformation in the South Mountain Fold, Maryland;" (1947) and "Microtectonics Along the Western Edge of the Blue Ridge, Maryland and Virginia" (1971).

In addition to his teaching and research, Cloos found time to serve as a consultant to several companies. His most extensive work was for the Thomasville Stone and Lime Company in Pennsylvania and the Humble Oil Company (later the Esso Production Research Company) in Texas. Cloos was involved in the Esso training seminar on structural geology where he taught his scale-model experiments using soft, wet clay. His scale-modeling sessions were the basis for his paper "Experimental Analysis of Gulf Coast Fracture Patterns" (1968). This paper won for him the American Association of Petroleum Geologists' President's award.

Cloos was quite active professionally. He belonged to many national and international geological societies and was especially active in the Geological Society of America and the National Academy of Sciences.

In 1923 Cloos married Margret Spemann. Cloos died May 28, 1974 and was survived by his wife Margret and their two daughters Gisela (married to W.R. Evitt) and Veronica (married to F.C. Evering).


13.76 Cubic Feet (6 record center cartons, 8 letter size document boxes, 4 legal size document boxes, 1 legal half-size document box, 1 flat box (15.5 x 12 x 3 inches), 1 flat box (11 x 9 x 3 inches), 1 custom box (14 x 10.5 x 4 inches), 1 custom box (10.5 x 8 x 5.5 inches))

Language of Materials



Ernst Cloos (1898-1974) was a structural geologist and professor at The Johns Hopkins University. The collection documents Cloos's field work and research through his meticulous, detailed field notebooks and research data dating from 1921-1980.

Immediate Source of Acquisition

At Cloos's death in 1974, his papers were sorted. The field and research materials were left in the Johns Hopkins University Geology Department. In 1989 these materials were donated to Special Collections by Cloos's widow Margret Spemann Cloos. A small group of Cloos's reprints and drafts of his last work Microtectonics Along the Western Edge of the Blue Ridge, Maryland and Virginia were donated to the University's Hamburger Archives and transferred to Special Collections in [1982].

Related Materials

Cloos' consulting work for the Maryland firm Harry T. Campbell Sons' Corporation was continued by Cloos's colleague Hans Eugster, and except for one report in Series 6, these related materials can be found in Eugster's papers, MS.0209, Special Collections.


This biographical sketch is drawn from F.J. Pettijohn's "Memorial to Ernst Cloos, 1898-1974" (1974). For more detail and analysis of Cloos's career see that memorial. A copy is in Series 1.

Processing Information

Finding aid prepared by Cynthia H. Requardt in 1989. The papers in this collection have been sorted but not completely analyzed.

Rachel Gattermeyer revised the scope and contents, biographical, and aquisition notes in this finding aid in November 2023 to bring it into compliance with Johns Hopkins guidelines for inclusive and conscientious description (2023). The previous version of the finding aid is available upon request.

Ernst Cloos papers
Language of description
Script of description
Language of description note
Finding aid written in English

Repository Details

Part of the Special Collections Repository

The Sheridan Libraries
Special Collections
3400 N Charles St
Baltimore MD 21218 USA