Those informational signs at various attractions can sometimes be more aptly described as mis-informational. This tends to frustrate the geotraveler: responses may include groans, gripes, and rolling eyes. One severely-annoyed geologist at Summer Lake, Oregon took matters (and a Sharpie) into their own hands, and engaged in a little correcting-their-fieldwork.

Crop of an informational sign explaining the tectonics of the Summer Lake region. "Pushed-together" is crossed out and "pulled-apart" is written above it in black Sharpie
The offending Summer Lake sign. Credit: Dana Hunter

If it's educational, is it still vandalism - or a public service? Asking for a geologist.

One sign that's just begging for the Sharpie treatment is this one at Deception Falls.

Detail of an informational sign showing three drawings with wording: the first speculates that a log jam forced the river to alter its course, the second postulates a layer of soft rock the river carged through, and the third illustrates the possibility of the river following a new fault.
Two plausible and one frankly impossible hypotheses. Credit: Dana Hunter

It's displayed at a fascinating part of the Tye River, where it goes from a broadish (if rocky) channel to a rather vigorous falls, and then makes a razor-sharp 90° turn to flow through a narrow, straight grandiorite channel.

Photograph shows a waterfall plunging at the right, into a channel that flows away at a right angle from it.
The river turns sharply! Credit: Dana Hunter

Wow, right? That's some dramatic geology, that is. Rivers don't usually do that.

The sign gives three speculations as to how this odd feature formed. Have a look at the video of the falls, and then see if you can spot the laughably ridiculous hypothesis:

1. Log Jam: Did a maclargehuge flood carry a load of logs down and dam the river, diverting it long enough to cut a new channel at a 90° angle to the original?

Pile of logs in the sunlight, with a large granitic cobble perched atop one.
Log pile left by flood waters at Deception Falls. Credit: Dana Hunter

2. Dike. Did the river erode away a dike of softer rock? The granitic bedrock at Deception Falls is cut by a myriad of dikes in various igneous materials.

Water streams past a broken dark rock cut with thin, pale dikes.
Small (possibly andesite) dikes cutting through bedrock. There are several large dikes of basalt and other igneous rock around the area as well. Credit: Dana Hunter

3. Fault. Did the river attack the crushed and broken rock of a fault, finding it easier to remove than unbroken bedrock?

A waterfall plunges through a rocky cleft in the mountainside, surrounded by verdant green trees.
A waterfall on Deception Creek plunges through a probable fault zone. Credit: Dana Hunter

Bonus geoblogosphere points shall be awarded to those who make a case for one or both of the remaining options.

A version of this post previously appeared at En Tequila Es Verdad.