Series. The amount of land covered by the map. A typical 7.5 series USGS map is 7.5 minutes of latitude high (about 9 miles) by 7.5 minutes of longitude wide (about 6 miles). A 15-minute series covering more land in less detail is also available.
High points. The innermost ring of a concentric pattern of contour lines resembling the whorl of a fingerprint. A peak is often marked by an X with the elevation noted.
Green. Woodlands and scrublands with substantial vegetation.