# Sources and rights

All 12 source sheets are public USGS National Geologic Map Database publications.

| Sheet | USGS publication |
|---|---|
| AK Dillingham | Wilson, F.H. (2018), *Surficial geologic map of the Dillingham quadrangle, southwestern Alaska*, SIM-3388. [NGMDB 107236](https://ngmdb.usgs.gov/Prodesc/proddesc_107236.htm) |
| AK Hughes | Hamilton, T.D. (2002), *Surficial geologic map of the Hughes quadrangle, Alaska*, MF-2408. [NGMDB 53758](https://ngmdb.usgs.gov/Prodesc/proddesc_53758.htm) |
| AR St. Joe | Hudson, M.R., and Turner, K.J. (2009), *Geologic map of the St. Joe quadrangle, Arkansas*, SIM-3074. [NGMDB 86691](https://ngmdb.usgs.gov/Prodesc/proddesc_86691.htm) |
| AZ Grand Canyon | Billingsley, G.H., and Hampton, H.M. (2000), *Geologic map of the Grand Canyon 30′ × 60′ quadrangle, Arizona*, I-2688. [NGMDB 34288](https://ngmdb.usgs.gov/Prodesc/proddesc_34288.htm) |
| AZ Pipe Spring | Billingsley, G.H., Priest, S.S., and Felger, T.J. (2004), *Geologic map of Pipe Spring National Monument and the western Kaibab-Paiute Indian Reservation*, SIM-2863. [NGMDB 70025](https://ngmdb.usgs.gov/Prodesc/proddesc_70025.htm) |
| CA/AZ Needles | Malmon, D.V., Howard, K.A., and Priest, S.S. (2009), *Geologic map of the Needles 7.5′ quadrangle, California and Arizona*, SIM-3062. [NGMDB 86429](https://ngmdb.usgs.gov/Prodesc/proddesc_86429.htm) |
| CA Elsinore | Morton, D.M., and Weber, F.H. (2003), *Preliminary geologic map of the Elsinore 7.5′ quadrangle, California*, OF-2003-281. [NGMDB 58858](https://ngmdb.usgs.gov/Prodesc/proddesc_58858.htm) |
| CA Marble Canyon | Stone, P., and others (2014), *Geologic map and Upper Paleozoic stratigraphy of the Marble Canyon area, California*, SIM-3298. [NGMDB 100304](https://ngmdb.usgs.gov/Prodesc/proddesc_100304.htm) |
| DC Frederick | Davis, A.M., and others (2001), *Geologic map database of the Washington, DC area*, OF-2001-227. [NGMDB 51791](https://ngmdb.usgs.gov/Prodesc/proddesc_51791.htm) |
| KY West Franklin | Moore, D.W., and others (2007), *Surficial geologic map of the West Franklin quadrangle, Indiana and Kentucky*, SIM-2967. [NGMDB 81180](https://ngmdb.usgs.gov/Prodesc/proddesc_81180.htm) |
| NH Hartland | Walsh, G.J. (2016), *Bedrock geologic map of the Hartland and North Hartland quadrangles, Vermont and New Hampshire*, SIM-3361. [NGMDB 104493](https://ngmdb.usgs.gov/Prodesc/proddesc_104493.htm) |
| OR Carlton | Wheeler, K.L., and others (2009), *Geologic map of the Carlton quadrangle, Oregon*, OF-2009-1172. [NGMDB 87512](https://ngmdb.usgs.gov/Prodesc/proddesc_87512.htm) |

USGS-authored or produced works are generally public domain in the United States. Some USGS publications may include third-party copyrighted material; that material remains subject to its original rights. See [USGS copyright guidance](https://www.usgs.gov/faqs/are-usgs-reportspublications-copyrighted) and [USGS data access and copyright guidance](https://www.usgs.gov/data-management/access-controls-and-copyrights).

The preview images in `examples/` are stripped, reduced-size copies of the cited public sheets and derivative overlays. No original full-resolution raster is included.