  We have examined in detail the morphologies of seven z~1.5 passively evolving
luminous red galaxies using high resolution HST NICMOS and ACS imaging data.
Almost all of these galaxies appear to be relaxed systems, with smooth
morphologies at both rest-frame UV and visible wavelengths. Previous results
from spectral synthesis modeling favor a single burst of star formation more
than 1 Gyr before the observed epoch. The prevalence of old stellar
populations, however, does not correlate exclusively with early-type
morphologies as it does in the local universe; the light profiles for some of
these galaxies appear to be dominated by massive exponential disks. This
evidence for massive old disks, along with the apparent uniformity of stellar
age across the disk, suggests formation by a mechanism better described as a
form of monolithic collapse than as a hierarchical merger. These galaxies could
not have undergone a single major merging event since the bulk of their stars
were formed, more than 1 Gyr earlier. There is at least one case, however, that
appears to be undergoing a "dry merger", which may be an example of the process
that converts these unusual galaxies into the familiar spheroids that dominate
galaxies comprising old stellar populations at the present epoch.
