It should be noted that more than one mine or prospect may be
associated with each map location on the plates. The location numbers
are not distinct between map sheets, so in these data the map_number
field was adjusted by adding the plate number multiplied by 1000 to
each original map number. So map_number values between 2000 and 2999
are located on plate 2, values between 3000 and 3999 are located on
plate 3, and so on.
The maps depicted on the plates did not differentiate feature types
graphically. Feature types specified in the feature field of the
points table are taken from the feature name, and points shown without
numbers are presumed to be unnamed prospects.
The map scales of the plates vary. Plates 3 and 6, which show the
largest number of features, are mapped at 1:62,500, while plates 2,4,
and 5 are mapped at 1:250,000. The consequence of this difference is
that we should expect the geographic locations to be more precise if
they were plotted on plates 3 or 6 than if they were plotted on plates
2.4. or 5.
The printed text contains numerous instances of words hyphenated
across lines. A few of these have been corrected, but some likely
remain in the descriptive fields.
Mines and prospect names that appear in parentheses in the report and
spreadsheet are separated into Other Names in the shapefiles attribute
Users should note that this information is not a substantive update of
the locations or characteristics of these mineral deposits or
operations. The report was published by USGS in 1968 and it is likely
that changes in the working status of mines and prospects have occurred
since then, and it may be that new deposits have been located which
were not known to the author of the 1968 report at the time.
Originator: Lesure, Frank Gardner
Title: Mica deposits of the Blue Ridge in North Carolina
Series_Name: Professional Paper
Publisher: U.S. Government Printing Office
Publication_Place: Washington DC
Source_Currentness_Reference: publication date
The subject dataset was created by digitizing this previously published work.
The paper plates and printed reports of USGS Professional Paper
577 were scanned at high resolution. The plates contain maps at
1:62,500 (3 and 6) and 1:250,000 (2, 4, and 5) scale; these were
geographically registered and the points digitized using ArcGIS
10.3. Table 4 of the report was converted to digital form using
Dragon voice recognition software with the exception of the
remarks field, whose contents were obtained by optical character
recognition software. The text of the report (pages 1-17) was
scanned at high resolution and subject to optical character
recognition as well; the result is provided as a PDF document
whose text may be selected or searched.
Contact_Person: Edward G Boyce
Contact_Position: Info Tech Specialist (Data Mgmt)
Contact_Organization: Midwest Region
Address_Type: mailing address
U.S. Geological Survey
Mail Stop 954
12201 Sunrise Valley Dr
Digital copies of the data for each plate (as shapefiles) and for
each part of table 4 (as Microsoft Excel documents) were converted
to SQL code for entry into the PostgreSQL relational database
using PostGIS geographic extensions.
Point and descriptive table row identifiers were disambiguated by
including the plate number in each ID field. Where tabular
information were listed as coming from plate "5 or 6" the records
were matched manually using the names of the sites to assign
correct ID values.
A number of simple corrections were made to name fields and other
data fields to remove extraneous punctuation, carriage returns,
and to establish one-to-one relationships between corresponding
rows in the points and descriptions tables.
For each record, an XML and a JSON representation of the complete
data record was created so that this information can be flexibly
re-expressed in the future using appropriate technology (at this
writing, 2016, reports of individual sites are composed by
transforming the XML representation of the data into HTML using an
A geospatial map service was configured to provide these data to
the public in the form of an Open Geospatial Consortium Web Map
Specification service. The data are provided in an interactive
web map interface using this service.
This metadata record was written to provide detailed documentation
of the history of this data conversion effort.
Contact_Person: Peter N Schweitzer
Contact_Organization: USGS ER GD
Address_Type: mailing address
Address: 12201 Sunrise Valley Drive