Basement windows: Help with a problem – GreenBuildingAdvisor

I have an 1850s farmhouse with a field stone foundation topped with granite blocks, and then sills.

There are ventillation holes inset into the granite blocks. They had no glass, just screens. And they are framed into wood.

When I bought the house, I had foam insulation installed in the basement and the spray foamer sprayed in the empty spaces to seal them off. Most of the windows now have an piece of exterior plywood installed over them out side and painted.

THere used to be window wells, but at one point landscapers removed them, and now the base of the windows (the wood framing) is covered with gravel.

I’ve been thinking the old windows should be replaced with something. It occured to me that insulated glass block might be really nice.

Not sure if that can be installed and have the gravel put up against it. Or to have a piece of granite in place of the old wood and the glass block installed above grade.

Thanks for your help!