  For the very best and brightest asteroseismic solar-type targets observed by
Kepler, the frequency precision is sufficient to determine the acoustic depths
of the surface convective layer and the helium ionization zone. Such sharp
features inside the acoustic cavity of the star, which we call acoustic
glitches, create small oscillatory deviations from the uniform spacing of
frequencies in a sequence of oscillation modes with the same spherical harmonic
degree. We use these oscillatory signals to determine the acoustic locations of
such features in 19 solar-type stars observed by the Kepler mission. Four
independent groups of researchers utilized the oscillation frequencies
themselves, the second differences of the frequencies and the ratio of the
small and large separation to locate the base of the convection zone and the
second helium ionization zone. Despite the significantly different methods of
analysis, good agreement was found between the results of these four groups,
barring a few cases. These results also agree reasonably well with the
locations of these layers in representative models of the stars. These results
firmly establish the presence of the oscillatory signals in the asteroseismic
data and the viability of several techniques to determine the location of
acoustic glitches inside stars.
