Bumblebee nest?

A couple of years ago, I bought a hedgehog house online and placed it under the huge rose bush in the garden. As it turned out, it was never used for hedgehogs because the garden board would not allow us to take in hedgehogs since there are badgers in the vicinity of the community garden, and they are known to kill hedgehogs. So the hedgehog house has been standing empty ever since, until recently. Last week I was cleaning up all of the dead leaves and refuse under the rose bush, and my eye happened to light upon something of interest inside the hedgehog house. It looked like a symmetrically-shaped ornament with a hole in the top. Upon closer inspection, I realized it was a nest of some sort. My first thought was that it was a bumblebee nest, since bumblebees do make their homes on the ground under protective coverings, e.g. an upside-down flower pot or a compost bin (as I have also witnessed this summer). I took a few photos of it in order to search online afterward. I am fairly sure it is a bumblebee nest. But if any of you have other suggestions, I'd love to hear them.