Bicentenial of the Geologic Map

People have been studying geology in some form for a very long time. But 2015 marks the 200th year of what is now a standard of geologic practice: the geology map. I got a close look at the first geology map back in 2012 and thought the bicentennial of William Smith's breakthrough accomplishment is worth another look. http://washingtonlandscape.blogspot.com/2012/10/the-first-geology-map-surpise-at-tate.html