<p>At first glance I'd say this looks like a granite but its hard to tell from the photos, certainly the rock looks to be a fairly massive (lacking structure). Looking it bit closer I'm now thinking it may be a coarse sandstone/conglomerate, judging by the large clasts that appear to be weathering out between the caves.</p>
<p>In either case, both sandstones and granites tend to weather 'spheroidally' into nice rounded shapes. My suspicion is that the rock has some compostional / structural susceptibility to surface weathering where these caves have been formed, perhaps exacerbated by being close to the waterline.</p>
<p>Its quite hard to tell without a proper look around though.</p>

CC BY-SA 4.0
2021-08-18T23:51:02.257Z
2021-08-18T23:51:02.257Z
Callum Strong
<p>I've been trying to figure out how these holes formed in the rock. These pictures were taken in Quebec, Canada on  small lake in cottage country. The strange thing is that they are almost both identical. There are no signs of tools used and the lake is very small with not many boats.</p>
<p><a href="https://i.sstatic.net/lRN9W.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/lRN9W.jpg" alt="enter image description here" /></a><a href="https://i.sstatic.net/c5iQU.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/c5iQU.jpg" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2021-08-17T16:10:19.783Z
what type of rock is it? please update your question with more details about the area.
trond hansen
<geology><rocks>
How did these holes form in the rock?
David A
# How did these holes form in the rock?

(Asked by: username_0 on 2021-08-17)

I've been trying to figure out how these holes formed in the rock. These pictures were taken in Quebec, Canada on small lake in cottage country. The strange thing is that they are almost both identical. There are no signs of tools used and the lake is very small with not many boats.

[![enter image description here](https://i.sstatic.net/lRN9W.jpg)](https://i.sstatic.net/lRN9W.jpg)[![enter image description here](https://i.sstatic.net/c5iQU.jpg)](https://i.sstatic.net/c5iQU.jpg)

**Tags:** geology, rocks

> **Comments:**
> **username_1**: what type of rock is it? please update your question with more details about the area.  

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## 1 answers

### Answer by username_2 on 2021-08-18. Score: 0

At first glance I'd say this looks like a granite but its hard to tell from the photos, certainly the rock looks to be a fairly massive (lacking structure). Looking it bit closer I'm now thinking it may be a coarse sandstone/conglomerate, judging by the large clasts that appear to be weathering out between the caves.

In either case, both sandstones and granites tend to weather 'spheroidally' into nice rounded shapes. My suspicion is that the rock has some compostional / structural susceptibility to surface weathering where these caves have been formed, perhaps exacerbated by being close to the waterline.

Its quite hard to tell without a proper look around though.


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