The present is NOT the key to the past. Except in microscopic environments like Mt Saint Helens. Ever noticed that alluvial fans are slopped downward? And all sedimentary deposits are produced by alluvial fans today? Or flood plains. And some are claimed to be the bottoms of lakes, or oceans. But none cover thousands of square miles today like those found in the geologic column. Which are also found on other continents on the other side of the earth.
The fact is the sedimentary deposition of the geologic column covers thousands of miles with dead flat layers from deposition without erosion. Many brief flat surface layers formed at this time have tracks, mud cracks, and ripple marks preserved by volcanic ash covering them, or soft sediment in a tidal impact.
Then the land arose. Then there was erosion from huge amounts of water flowing toward the ocean, forming canyons with no deposition. And producing plateaus of un-eroded flat material deposited in a temporary inland sea. By the way, seas are never found on continental land today. This indicates these were oceanic incursions caused by a cataclysm.
Huge wide canyons do not form by small rivers over a long period of time. They require large amounts of water flowing rapidly. Small amounts produce narrow cuts in rocks, only large rivers produce large canyons.
Here is a typical canyon formed by a small amount of water.
And her is what happens when a large amount of water decreases to a small amout and becomes a meandering river.
This is a small river in an over-sized valley.
Now this meandering river did not form this valley. Notice that the rest of the valley is not being eroded.
Here is a geologic map to show nothing like the formation in the past are forming today. These cover millions of square miles, including other continents.