How do I tell if class E airspace extends to surface or starts at 700'? I am confused about where class E airspace starts in the USA. If it has dotted magenta lines does it start at the surface? If small airport has round magenta circle but no dotted lines does class E start at 700'?
Source: FAA VFR chart.

The magenta dashed is from surface, the magenta gradient is from 700 ft. AGL, and the blue gradient from 1200 ft. AGL.