I have spent many days and nights on the river - over the years sailing between Manhattan’s lower harbor and Kingston, NY. I became fascinated by the point at which the water met the shore, particularly when the shore was almost perpendicular. The shapes of the Hudson Highlands tempt the viewer with a hint of the geology below. Carl Carmer’s book “The Hudson”, contains a thrilling description of the rivers geologic past. - Margaret Grace “A generally accepted theory is that at some time before the existence of man the water level of the Atlantic dropped ten to fifteen thousand feet. When the last of the four great ice sheets was on the land, a mighty river gushed from the end of the glacier that had covered the Hudson valley and roared downward, cutting deep into the soft sediment of the former ocean floor, to a new shore line nearly 150 miles farther out that the old one. For thousands of years the great stream ran, constantly lowering its level and digging dropped steeply until in some places it reached a depth of 3,600 feet, a thousand feet deeper that the Royal Gorge of the Colorado. Had there been human life then, a traveler in a boat on the Hudson might have looked up to the blue sky between the walls more than two miles high. But no man has yet seen, or probably ever will see, this stupendous natural phenomenon. After the river had created it, the salt sea returned and buried the canyon thousands of feet below tossing waves.” “Near the edge of the continental shelf-the elevation a hundred miles above the ocean floor, which geologists believe was once dry land - the Hudson River makes one last plunge downward. The grade is so steep that the 1,200 foot drop has been called the “undersea falls”. Carl Karmer, “The Hudson”, 1939.