Here are pictures of the old and the new.
Decided to leave the wall-trim board off.
Should be pretty self-explanatory.
The new shelf is actually a sofa table with the legs sawn off and diagonal braces added on the underside to stabalize for wall mounting. The rear edge of the top is also sawn off so the back of the table sits against the wall. Unfinished pine from Marty's Jungle just North of Utica off Route 12. Funished by Jeanne.