Combine crumbs and margarine, press onto bottom of 9 inch spring form pan. Bake at 350 degrees for 10 min.
In 1.5 quart heavy saucepan, melt caramels with milk over low heat, stirring frequently, until smooth. Pour over crust. Top with pecans. Combine cream cheese, sugar and vanilla. Mixing at medium speed on electric mixer until well blended add, eggs one at a time, mixing well after each addition.
Blend in chocolate; pour over pecans.
Bake at 350 degrees, 40 min. Loosen cake from rim of pan
Cool before removing rim of pan.
Chill. Garnish with whipped cream and additional finely chopped pecans, if desired.