Opalescent Brook,Photograph by Croswell Bowen, 1939
So wrote Carl Carmer, in 1939, describing the source of The Hudson in the Adirondacks. The acceptance of tectonic plate theory in the 1970s changed much in American's favorite science: Geology.
I wonder if Carl's description of the geology of the Hudson Valley holds up?
On my Great River Revisited journey, I will speak with an authority on this matter: Donald W. Fisher, retired New York State Paleontologist. I will visit him at Fisher's O.K. Rock Shop in Kinderhook!
Meanwhile, I'm reading his The Rise and Fall of The Tectonic Mountains: A Geological History of Eastern New York. It's fronted with a terrific geologic map of New York State, funded by a grant from Furthermore. I have learned from this terrific book: the Hudson is the by product of eons of amazing changes to the earth's surface.
It's my guess that most of Carl's description will hold up. In his acknowledgements, he thanks Lt. Paul Smith, of the U.S. Coast and Geodetic Survey. Smith oversaw the undersea mapping and aeronautical charts undertaken just before the beginning of World War II, in time for Carl to be aware of the surprises held by undersea mapping.
