| Publication Type: | Journal Article |
| Year of Publication: | 1977 |
| Authors: | J. W. Wells |
| Journal: | United States Geological Survey Professional Paper |
| Volume: | 640-G |
| Pagination: | 1 - 13, pl. 1-3 |
| Date Published: | 1977/// |
| URL: | http://pubs.er.usgs.gov/publication/pp640G |