Heat oven to 425F. Grease large baking sheet.
In large bowl, combine flour, sugar, baking powder,
salt and baking soda. With pastry blender or 2 knives,
cut in butter until mixture resembles coarse crumbs.
Remove 1 1/4 c. flour mixture to medium-size bowl.

In small bowl, combine buttermilk and vanilla.
In cup, combine 1/4 c. buttermilk mixture
and chocolate. Add remaining buttermilk mixture
to remaining flour mixture in large bowl and
mix lightly with fork until mixture clings together
and forms a soft dough. Add chocolate mixture
to the1 1/4 c. flour mixture and stir with
fork until it forms a soft dough.

Turn both doughs out onto lightly floured surface;
divide chocolate dough into 6 pieces.
Dot 3 chocolate pieces over surface of plain dough.
Fold dough over and dot with remaininng 3 pieces;
knead gently 5-6 times to marbelize dough.
Divide dough in half. With lightly floured rolling pin,
roll one half into a 7" round. Cut into 4 wedges.
Repeat with remaining half of dough.
Place scones, 1" apart, on greased baking sheet.
Pierce tops with tines of fork.
Bakes scones 15-18 min. or until golden brown.
Serve warm.