I asked local Geologist Arthur Troell to review maps of the area surrounding the old Breaker home, Cockrell Canyon and Crain (Crane) Road. He also went out to the canyon.
Troell said, “That’s a gully or a ravine. Well, a kid would call it a canyon because, to a kid, it looks that way. When they’re little kids and they come out there, compared to them in the scale that they look at things like this, it looks big.
“They probably haven’t seen too much else in the landscape such as this. So it’s 20, 30 feet deep and to them it looks huge.
“The Galvan Creek that the gully/ravine (Cockrell Canyon) joins is a stream that’s meandering back and forth and, geologically, it’s what we call a ‘cut bank of that stream’. And the canyon area is all higher level. The drainage there has cut a stream that’s emptying into the Galvan. The gully/ crevice eroded and is a dry stream that flows only when it rains.”
Troell continued, “If it was 200 feet deep, we would probably call it a canyon.
“For example, Medina Lake is the dammed up Medina River Canyon. Canyon Lake is a dammed up Guadalupe River and that’s a canyon.
“It’s a matter of scale. And the scale here is much smaller and I can understand how kids in that area – playing cowboys and Indians, whatever their playing – they’re going up in there and exploring and, to them, it’s a canyon.
“All the way across the country we’re looking at all kinds of scales of things. To geologists, we’d call Cockrell Canyon a gully or a ravine. It’s a ‘cut bank of a stream’.
“You have the coast, the stream can’t cut its valley below the level of the Gulf of Mexico. That’s what we call ‘base level’, it can’t be cut below it. We raise the land up – the land is higher than the sea and streams can start eating their way back into the landscape. And they cut a valley and that valley’s controlled by the Gulf of Mexico which is the base level.
“The control level of the Galvan is the base level that would be the level of the Atascosa River.
“The level of the gully/ ravine (Cockrell Canyon) is controlled by the level of the Galvan Creek.”