About the Site

Washington Monument

Scope of the website.  

This website aims to describe, or at least list, all of the public fossils occurring in Washington’s architectural landscape.  The Galleries discuss particularly interesting fossils and how they became part of the urban scene.

It includes only fossils that are:

  • Public.  Fossils found in non-public areas – in office buildings, inaccessible behind guard desks, for example -- are not included.   Streets and museums are always public; lobbies are more problematic and vary case-by-case.  
  • Recognizable.   Most types of limestone are of biological origin, but many do not have fossils visible to the unaided eye.  True marbles will sometimes display heavily metamorphosed fossils best described as “blotches.”  Only fossils that can be recognized – even if in fragments -- are included.
  • Not a museum exhibit.  For example, the huge chunk of petrified stone found outside the Smithsonian Museum of Natural History’s Mall entrance is an intentional exhibit of an actual museum.  It is not part of the Accidental Museum.  

Why was this website created?   The author walks about the city extensively.  Over time, it became apparent to him that many buildings and other structures displayed a wide range of fossils.  Yet, with the exception of a few brief references in the USGS’s Building Stones of Our Nation’s Capital, a few, little-publicized pieces by and about the late Prof. James O’Connor, and scattered other published references, almost no information was published about the nature, age, and source of the fossils.

This website is intended to provide that information and to publicize the existence of the city’s “Accidental Museum of Paleontology.”  Across the city, every day people pass by fossils ranging from the Paleozoic to the present, as they live, work and visit.  The author believes that someone should provide a guide to this remarkable, public fossil display.

The website also discusses at least some of the architectural context for the fossils.  The author is interested in why the fossil-bearing stones were chosen and in the architectural history of the sites.

Taxonomy (def. “the science of classifying organisms into groups by structure, origin, common ancestor, etc.”)  This website is only one variant of a larger family of guides to urban geology, which are available online and in pamphlets.  This is not even the only geology guide for D.C. architecture.   The greatest example of such geology guides is the United States Geological Survey’s Building Stones of Our Nation’s Capital, available in full at the USGS website.  Building Stones is unparalleled in general scope and content, though it deals only briefly with fossils.  Other guides abound, including the following:

A Geologic Walking Tour of Building Stones of Downtown Baltimore, Maryland, http://www.mgs.md.gov/esic/features/walking/index.html  

Guide to the Building Stones of Downtown Cincinnati: A Walking Tour: Field Trip Guidebook No. 7, Geol. Soc. America Annual Meeting, Ohio Geological Survey, 44p.  by Hannibal, Joseph T. and Davis, Richard Arnold, 1992,

As part of its celebration of Earth Science Week 2000, the Ohio Division of Geological Survey and the Ohio Section of the American Institute of Professional Geologists co-sponsored three one-hour walking tours to explore the rocks used for building stones in three Ohio cities. The field trips were based on the series of guidebooks (GB 5, GB 6, GB 7) published in the early 1990's by the Survey. The descriptive brochures for the three trips are available in PDF format.

Building stones in the vicinity of Capitol Square, Columbus, Ohio
Building stones in the vicinity of Public Square, Cleveland, Ohio
Building stones in the vicinity of Fountain Square, Cincinnati, Ohio

A Tour Guide to the Building Stones of New Orleans, Louisiana: New Orleans, La., by Slagle, Edward S., 1982, The New Orleans Geological Society, 68p.

Walking Tour of Downtown Houston Building Stones, Houston Geological Society, 1995,: Research Committee, Philip W. Porter, Chmn., 39p.

Walking the Forty Acres: Building Stones – Precambrian to Pleistocene,  by S.P. Ellison and Joseph J. Jones.    http://www.lib.utexas.edu/geo/fortyacres/40acres3.html  

Geology Along Michigan Avenue, presented by Ellin Beltz (photographs).

Geologic Glimpses from Around the World - The Geology of Monuments in Woodland Cemetery and Arboretum, Dayton, Ohio: A Self-Guided Tour, by M. R. Sandy, 1992, Ohio Division of Geological Survey Guidebook 8 (Book).

Guide to Stones Used for Houses of Worship in Northeastern Ohio, by Joseph T. Hannibal, Curator of Invertebrate Paleontology at the Cleveland Museum of Natural History. The Urban Center's Sacred Landmark Series.

Building Stones of Downtown Chattanooga, by Robert Lake Wilson,


Geology Tour of Denver's Buildings and Monuments, by Jack A. Murphy, publisher: Denver, Colorado, Historic Denver in cooperation with Denver Museum of Natural History, c1995, ISBN:0914248065. (Book)

Building Stone Walking Tour, presented by the Utah Geological Society. Public Information Series #60. http://geology.utah.gov/online_html/pi/pi-60/pi60pg4.htm

Cornerstones of Spokane, A guidebook to the building stones of downtown Spokane, Northwest Mining Association, http://www.dnr.wa.gov/geology/pdf/spoktour.pdf

Dimension Stone in Victoria, British Columbia, a city guide and walking tour, by Z. D. Hora and L. B. Miller.

Learning Geology from Buildings in Downtown Toronto, Canada, by Kathleen Kemp, Tucker Barrie, Marcia Charles, Janet Parkin, Denise Payne and Michael Perkins.

The Building Stones of Dublin: A Walking Guide, by Patrick Wyse Jackson, photography by Declan Burke, publisher: Dublin, Ireland, Town House and Country House, 1993, ISBN:0946172323 (Book).

The Gloucester Wall Game: London, by Eric Robinson, no date, London Geologists' Association.

About the author.  The author, Christopher Barr, is a lawyer who has lived in Washington, D.C. since 1979.  Although the author’s B.A. was in history, he also took several geology courses in college.   It is to the instructors in those classes – Prof. Brian Skinner, the late Prof. John Ostrom, and then-doctoral candidate David Jablonski – and to their infectious enthusiasm for the study of geology, that the author attributes his continuing interest in paleontology.  The author and his family have been members of the Gem, Lapidary and Mineral Society of Montgomery County (Md.) and have made a number of fossil collecting trips in this region and elsewhere.  (Needless to say, none of the fossils discussed in this website are candidates for collection.)

Acknowledgments.   The author’s wife, Patricia Jayne, assisted with photographs and images and provided advice regarding the website; without her help and encouragement this project would have gone nowhere.   The author’s daughter, Judith Barr, took many photographs and provided many helpful suggestions.  Nitt Chuenprateep, a government and studio art student at Claremont McKenna College, designed the template and constructed the website.  Philip Barr, an engineering student at Penn State, and the author’s son, also assisted in the design and construction of this website.  The author is only an interested amateur, and without the help and assistance of many geologists, archivists, librarians and others with information about the fossils and buildings, this website would not exist.  They are numerous, and each Gallery recognizes those who assisted in providing information about specific fossils or structures in a closing discussion.  Callan Bentley, a member of the geology faculty of Northern Virginia Community College who himself leads geology trips into the city, very helpfully read a draft of the entire text and provided numerous substantive and editorial suggestions.  The reference librarians at the Washingtoniana Collection of the D.C. Public Library and at the Library of Congress were also extremely helpful.  All errors or misstatements in this work stem from author rather than those he consulted.