I see that shadowy area too. I doubt a culvert or anything manmade at that depth. I would guess a more permeable layer of rock/sediment. It appears to be at a similar elevation to the base of the upper cliffs to the east and west. Hopefully someone with boots on the ground can provide more info.
Nice video terry1million. Went there and saw it myself had a close look. I would call it a LAND slide and dictionary definition for land slide ..... a collapse of a mass of earth or rock from a mountain or cliff. Check it out on Google grahvis before you attempt to be little people
@@Amanda-cd1ue . How did I belittle anyone? There is a big difference between a rocky cliff and what is little more than an earth bank which we see in the video. That difference is what means one will slide far more easily than the other.