TY  - RPRT
TI  - Map showing potential sources of gravel and crushed-rock aggregate in the Colorado Springs-Castle Rock area, Front Range urban corridor, Colorado
AU  - D. E. Trimble
AU  - H. R. Fitch
PY  - 1974
DO  - 10.3133/i857a
UR  - https://pubs.usgs.gov/publication/i857A
ID  - i857A
ER  -