  A characteristic pattern of solar hard X-ray emission, first identified in
SOL1969-03-30 by Frost & Dennis (1971), turns out to have a close association
with the prolonged high-energy gamma-ray emission originally observed by
Forrest et al. (1985). This identification has become clear via the
observations of long-duration gamma-ray flares by the Fermi/LAT experiment, for
example in the event SOL2014-09-01. The distinctive features of these events
include flat hard X-ray spectra extending well above 100 keV, a characteristic
pattern of time development, low-frequency gyrosynchrotron peaks, CME
association, and gamma-rays identifiable with pion decay originating in GeV
ions. The identification of these events with otherwise known solar structures
nevertheless remains elusive, in spite of the wealth of EUV imagery available
from SDO/AIA. The quandary is that these events have a clear association with
SEPs in the high corona, and yet the gamma-ray production implicates the
photosphere itself, despite the strong mirror force that should focus the
particles \textit{away} from the Sun We discuss the morphology of these
phenomena and propose a solution to this problem.
