Was the Galaxy's halo built from tidally disrupted smaller galaxies?

Kinematics and abundances of the Milky Way halo:

By measuring the velocities and [F/H] for many stars in the Galactic halo across large patches of sky, one can search for "strings" in the 5-space (RA, Dec, distance, velocity, [Fe/H]) that are the signature of tidal tails and disrupted small galaxies. Projects to do this survey are underway, but the large field and number of simultaneous spectra that this telescope offer make it possible to be highly definitive about detections of tails. For example, one can observe 100 sq.deg2.(50 pointings) in about a week.

This image (from Kathryn Johnston) shows how a several dwarf galaxies might be stretched into tidal tails as they orbit the Milky Way galaxy.

This image (from Paul Harding) shows how many dwarf galaxies might be transformed into the stars that we call the halo of the Galaxy.