Purgatory Canyon, Arizona - 7.5 Minute Series Topo Map Shallow Groundwater Pages: 328 p

Pages: 328 p

and geologic symbols

including the Black Rock sites

The valley floor is covered by Quaternary lacustrine and marsh deposits

Previous mapping of the quadrangle is limited

Purgatory Canyon, Arizona - 7.5 Minute Series Topo Map Shallow Groundwater Pages: 328 pThe distinctive characteristic of a topographic map is that the shape of the Earth's surface is shown by contour lines. Contours are imaginary lines that join points of equal elevation on the surface of the land above or below a reference surface, such as mean sea level. Contours make it possible to measure the height of mountains, depths of the ocean bottom, and steepness of slopes. A topographic map shows more than contours. The map also includes