Archive for September, 2008


Revised 10/22/2008

AutoCarto 2008 Web Submission


The history of GIS can be traced to include the work of Henry Thoreau and
his land survey and map-making activities from 1847 to 1860.  Concord’s
Upper Mill Brook has a fascinating history of map truth evolution and map error
discovery and rediscovery by Thoreau, H. F. Walling, Herbert W. Gleason, USGS
and others.


Thoreau, survey, Concord, Walden, Brister’s Spring, Mill Brook, H. F.
Walling, Herbert W. Gleason, USGS


Thoreau’s land survey and map-making activities from 1847 to 1860 produced
191 land surveys and drawings including three maps of “John B. Moore’s
Farm” in 1853 and 1860 (twice).  These three survey maps provide an
invariant time series record of Concord’s Mill Brook bridges crossing
Hawthorne’s Lane and Cambridge Turnpike. 

Maps of Concord produced by others including H. F. Walling’s 1852 Concord
survey, USGS 1894 Reconnaissance map of Concord and Herbert W. Gleason’s 1906
map of Concord mislocated those Mill Brook bridges.  In 1943 USGS and
subsequent maps resumed correctly locating the Mill Brook bridges as defined by
Thoreau. WHY?  Thoreau’s 1853 map was based upon a true engineering survey using chain and compass whereas H. F. Walling’s 1852 map of Concord provides a less precise
cartographic definition of hydrologic features outside of Concord’s Town Center including
the Mill Brook’s bridges.  Later maps produced by both the USGS in 1894
and Gleason in 1906 may have used the 1852  Walling data which then were
then the current local maps thus perpetuating the error.  It was not until
1943 when the USGS conducted its photogrametric survey that Thoreau’s more
accurate location of the Mill Brook bridges was once again correctly

This evolution of map error and eventual rediscovery of map truth is an
interesting historical artifact but perhaps no more so than Thoreau’s and USGS’s inability to
realize that Walden Pond waters flow under Brister’s Hill and emerge at
Brister’s Spring a quarter mile away at a frequently visited drinking spot
immortalized by Thoreau as the source of the Mill Brook.  Although Thoreau
in the 1850’s collected over 800 wildlife specimens for Louis Agassiz’s Museum
at Harvard, Thoreau did not appear aware of Agassiz’s theory of glaciation so
evidently demonstrated by Walden Pond and Brister’s Spring.  Rather,
Thoreau spoke frequently of Walden Pond as being an artifact of the biblical
great flood as did the majority of people of his time. 

In 2000 USGS reported that Walden Pond probably
seeps into the Mill Brook but did not suggest a Brister’s spring
connection.  In 2005 Schmidt hypothesized a Brister’s Spring-Walden Pond
In retrospect, Concord’s Upper Mill Brook has a
fascinating history of discovery and rediscovery by Thoreau and others.


  • 1837 Henry Thoreau receives
    his degree from Harvard College, graduating 19th in a class of

  • 1845-47
    built himself a small
    house on the shore of Walden Pond.

  • 1846
    Thoreau surveys Walden Pond.

  • 1847 Thoreau writes of
    enjoying Brister’s Spring water while living at Walden Pond.

  • 1847 LouisAgassiz appointment
    as Professor of zoology and geology at Harvard. 

  • Thoreau developed a serious
    interest in botany, especially after meeting Louis Agassiz, with whom
    Thoreau corresponded, and for whom he later collected wildlife specimens.
    Over a ten-year period Thoreau was able to identify more than 800 species
    in Middlesex County.

  • 1848 Agassiz announced his
    theory of glaciation to the Royal Society of London. 

  • Uniformitarian geologists
    preferred the glacial theory to the former explanation that observed
    phenomena such as Walden Pond, were largely due to the Flood at the time
    of Noah.

  • 1852 H. F. Walling’s Concord
    survey mislocates two Mill Brook bridges.

  • 1853-1860 Thoreau surveys
    Walden Pond, the Mill Brook and 150 other locations using chain and

  • 1894 USGS Framingham map
    mislocates two Mill Brook bridges similar to the H. F.  Walling map.

  • 1906 Herbert W. Gleason maps
    The Mill Brook with Walling data but as a marsh without a defined stream

  • 1943 USGS map of Concord
    surveyed the Mill Brook with bridges located as Thoreau did in 1853 and

  • 2000 USGS reported that Walden Pond probably seeps into the Mill Brook
    but did not suggest a Brister’s spring connection.

  • 2005
    Brister’s Spring-Walden Pond connection hypothesized


Concord’s Upper Mill Brook has been mapped several times between 1852 and
1906 with consistent location hydrologic data error relative to Thoreau’s more
accurate 1853 and 1860 surveys.


Map error can be propagated by use of currently accepted map truth.

H. F. Walling’s 1852 Map of Concord, USGS’ 1894 Reconnaissance map and
Gleason’s 1906 map of Concord should be used with caution and compared when
possible to 1943 and later USGS maps.


Thoreau’s 1853 map  of  John Moore’s Farm may be viewed at:


Thoreau’s April 1860 draft map of John Moore’s Farm may be viewed at:

of John B. Moore’s Farm … Apr. 1860 [apparently the draft for printed plan

Thoreau’s May 1860 final map may be of John Moore’s Farm may be viewed at: http://www.concordlibrary.org/scollect/Thoreau_surveys/94b.htm 

H. F Walling’s 1852 map may be viewed at:


USGS 1894 Reconnaissance Map may be viewed at:


Gleason’s 1906 Map

Gleason’s 1906 Concord map may be viewed



Walter Brain provided valuable assistance and correction to my interpretation
of Thoreau’s Surveys on-line at the Concord Free Public Library.
On-line access to Thoreau’s Surveys provided  “Courtesy Concord Free Public


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