A river ran through it.

Visualise a mountain range some 100 miles long and anything up to 10,000' high. Now imagine a river approaching it from a right angle and carving a gradual passage through the very centre of that range to create a water gap through which the river can eventually run freely at the base of those mountains.
I think you can agree with me that such a process of gradual erosion through solid rock would probably take many millions of years to achieve, even where we are only talking in hundreds of feet.
One tiny little problem however - so small I almost hesitate to mention it - the idea is complete and utter tommy rot.
We have been sold a pup. We have been presented with an idea which only sounds logical but is far from being so.
Stop and ask yourself how water actually works outside non-evolutionary fantasies. Well, does a river approach solid rock and start planning ahead by millions of years OR does it flow all around the base of the mountains using a combination of gravity and the line of least resistance? If you ask a uniformitarian geologist, they have to go onto the defensive and postulate a host of highly unlikely scenarios which become increasingly desperate and unbelievable.
A simple proof that uniformitarian geology is a load of you-know-what.
What really happened do I hear you ask? - Ah well. The river as a torrent forced its way through - probably in a matter of days when the rock was soft and it was the least resistant point.
Long age geology - 100% wrong - and the believable model rather more in line with a different deluge and a considerably reduced timeline.
Remember that glaciation - another idea abused by long time period geologists is not an issue here.
Consider also the shape of these gaps. Look at the photo. Now ask yourself why the gap is a wide vee shape.
Surely it would be more logical to have sheer sides or even a tunnel. You cannot argue that the water 'has been going through the upper reaches for longer' because the river 'drops' as it allegedly erodes.

SOURCES:
http://www.creationontheweb.com/content/view/5064 Michael Oard. MSc. "Do rivers erode through mountains?"

"The Missoula flood controversy and the Genesis flood." Michael Oard. CRS Monograph 13.

The photo is of the Snake River.