Do snails dig holes to lay eggs?

I have repeatedly observed the snails in my back garden digging into my freshly sown lawn. On removing them they leave a hole about 3-4cm deep, one had even laid its eggs and they were clearly visible. Fascinated, I tried to 'harvest' them for a bit of a science project with my daughter but squished them in the process! I am fascinated by this behavior as it is something I have never seen before.