The rock coarsened abruptly as we drove on westward. There were cobbly conglomerates. They were the first explosive belch from the new Acadian mountains, which came up in the east at a rate ten times as fast as erosion could destroy them and, with a new system of rivers, rapidly shed this downpour of rock. A few miles farther on, another ten or fifteen million years, and we were among roadcuts containing upper Devonian stream channels of a quiet country, a low alluvial plainpoint bars, cutbanks, ripple marks in red river sands. We were forty million years past the Water Gap, and the geology was repeating itself on an epic scale. A new set of coalescing fans had come off the Acadian mountains, and, as the great sierra disintegrated, its co-working space utrecht detritus spread westward thick upon the country and into the seaat least ten tl1ousand feet thick in the east and gradually thinning to the west, this immense new elastic wedge, to be lmown in geology as the Catskill Delta. It stands at the surface of a huge piece of country. Erosion working into the high eastern end has cut the shapes of the Catskill Mountains. The rock lies essentially flat there, and is flat all the way to the shores of Lake Erie. It is the uppermost rock of half of New York State. It is the rock of Chenango, the rock of Chautauqua, too. It is the rock of Seneca, Ithaca, Elmira, Oneonta. In Pennsylvania, it is largely buried, or was sliced and lmeaded into the deformed mountains, but as the so-called Poconos it stands flat and high. The Poconos actually are part and parcel of the New York Devonian elastic wedge. The co-working space rotterdam Poconos are a tongue of New York State penetrating Pennsylvania. The Acadian mountains are gone. The wedge remains. The Acadians, in their Devonian prime, must have been a crowd of Kanchenjungas, to judge by their sedimentary remains, which reach almost to Indiana. As the mountains came down, they stood ever deeper in debris. At Denver, the Rocky Mountains are up to their hips in their own waste.