Fly Cemetery (aka "Dead Fly Pie") is a fruit slice - pastry top and bottom and a general mishmash of dried fruit and goo in the middle (currants, raisins, etc. usually glued together with apple gunge).

It's available in one form or another in most bakeries or teashops in England (and in The Ulster Museum in Belfast), but I've only really heard it called that regularly by Cambridgeshire people (where I was brought up).

:-)
Ian