This tunnel has a nice rounded pheratic shape that leads inward from the wave cut exterior of a low cliff face – in to the more spacious area that JC and I explored. As mentioned there is still exploration to be done and by the air blowing down one of the tubes we are optimistic that there is still some space beyond.
The thing about this cave that is really intriguing is that it exhibits features of multiple cave forms. As we discussed in a recent e-mail …
“In light of the placement of the lake, I wonder if this was the drainage conduit?
I envision a scenario where the lake was high, the joints in the rock were beneath the water table and the pheratic/rounded tunnel formed. As the lake level dropped, the lake behind continued draining along this passage, cutting a groove in the base of the tunnel. No doubt wave action would have played a part in the wave notch up front, but primarily this would have been a solution cave – following along crevices etc formed by the pull of glacial weight (like Mt. Nemo – but I guess Mt. Nemo does not show such obvious signs of pheratic development – it’s all crevice there) Difference is, there was no lake at Mt. Nemo to continue the wear process and alter pheratic passages (pheratic passages that may have formed along joints that had already pulled quite wide open) into vadose passages.
What do you think? Does this suggest other likely scenarios in every such lake placement? I see a cave here with wave cut features, solution features and crevice cave features – a cave that exhibits 3 distinct cave forms.
Then again I could be well off track; we should scour the shores of the Broken Rowboat Lake and see if there are other possible tunnel entrances.
Are you up for next weekend? The leg is better.”