Theres this video doing the rounds on youtube - https://www.youtube.com/watch?v=n0oQqX0Yugs
(sorry if this has been posted already but I did a search and couldn't see anything)
It's fairly long at 1hr 20min - the info I found interesting starts about 10 minutes in.
This guy rekons that volcanic plugs such as Devil's Mountain are the stumps of ancient giant silicon trees. The images he shows seem compelling enough for discussion. He goes off tangent in the 2nd half of the video and starts talking about how some mountain ranges are giant ancient quarries that were mined which I think is getting a bit on the silly side of things, but whatever. I'm more interested in the tree stump comparison. Any geologists on here want to shed any light on this? The guy's accent is a bit demanding but if you can make it through to around halfway theres some food for thought.