We show that some high Karlovitz number fuel-lean premixed jets burning in the products of richer pilot flames have stratified reaction zones. Laser Raman scattering measurements show that the equivalence ratio in the reaction zone does not correspond to the jet equivalence ratio, but intermediate values between the equivalence ratio of the jet and pilot. The distribution of equivalence ratio in the reaction zone depends on the turbulence intensity and position in the flame. The flames were not locally extinguished, indicating that the stratification was due to rapid turbulence-induced mixing occurring concurrently and coincident with the reactions. Properties of turbulent flames such as these should not be referenced against those of a laminar flame with the composition and conditions of the reactant jet, as this does not represent the chemistry in the reaction zones. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.