It seems that the cave geography repeats itself. To a farmer it is a curse but to me this sinkhole is very much like the Blue Barrel Sink and as you might already be aware, there is cave tunnel beneath Blue Barrel sink. and again, just like blue Barrel sink there is the surface depression that connects to the nearest sinkhole in the patch of trees in the distance.
Ontario’s karst geography is screaming “CAVE” and so few can hear the noise. Put your ear down in the bottom of this sink at springtime, when the snow is melting and if you can hear the same roar that JC and I heard from the river beneath Blue Barrel, well then you know to dig and you’ll open up a cave. This whole are is pocked with sinkholes, but most are taking surface streams.
This steep sided cone-shaped sinkhole seems indicative of soil being eroded from beneath. If you are searching for caves in Ontario, this is a very good indicator that there is a tunnel below. I think that those larger tear drop sinks that take small streams are seldom home to larger tunnels, but where the tunnels all meet up underground in a single trunk passage, that is the real prize. Without apparent surface flow, these dimples in the field are likely to be your most profitable use of time – they are eating soil because there is water flowing beneath.