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Maps at Carleton

Sample USGS Maps

A 7.5 minute map of the Northfield Quadrangle, circa 2013. (USGS)

A 1:250,000 Scale Map of the St. Paul area, circa 1953. (USGS)

USGS Maps in GovDocs

A selection from a geologic quadrangle map.

The USGS issues many reports and many of these report are or contain maps. A lot of these maps are cataloged as GovDocs and can be searched using Catalyst. You'll know you've found one when you see a listing marked:

"CARLETON Government Documents Map in File Cabinets (2nd fl.)."

However, not all of these documents appear in the catalog. Geologic and Hydrologic Quadrangles, Miscellaneous and later Mineral Field (after number 856) maps are generally in the catalog. Land Use, Oil and Gas, International and earlier Mineral Field maps (before number 856) are generally not in the catalog.

SuDoc Numbers

The file cabinets on Second Libe are marked with their contents, but you can also tell which of these categories a USGS map or report falls into by its SuDoc number (for more on the SuDoc classification system, look at the Government Documents research guide). These numbers are usually printed on the folders the maps are stored in.

A SuDoc number looks like this: I 19.88:GQ-612.

The number printed on an envelope containing a map:

Notice that the letters and number after the colon are separated.

All USGS maps are going to have SuDoc numbers begining with I 19. The numbers that come after the colon are most important for us. The letters after the colon denote what kind of map you're looking at. The numbers after dash denote where the map can be found. Here are the letter codes that Carleton has maps corresponding to:


HA-Hydrologic Quadrangles

GQ-Geologic Quadrangles

MF-Mineral Field Investigations

OM-Oil and Gas Investigations

L-Land Use

MC-Geological Society of America


Carleton does have indices of USGS maps of particular locations, however, they were printed in the 80's and might be dated.

A USGS geologic quadrangle map at Carleton