  In this paper, a probable interpretation of a remarkable fine structure of
all particle spectra between the knee and the ankle, as well as a high content
of heavy nuclei around 10^17 eV measured recently in Tunka-133 and KASCADE
Grande experiments, is presented in the model where production of cosmic rays
in Type Ia SNRs provides observed cosmic rays (CR) flux around the knee.
Subtracting the contribution of these sources from all particle spectrum we
obtained the residual flux of CR in the transition region between Galactic and
Extragalactic CR in the range 10^17-5 10^18 eV. The obtained spectrum also has
a pronounced knee at energy (2-3)10^17 eV and slopes g1 ~ 1.8+-0.3 below it and
g2 ~3.4 above it. We analyzed the possible contribution from known Galactic
sources and found that formally the best candidate to contribute significantly
to the transition region is Cas A. This source posses a number of unusual
properties and considered as Type IIb SNR. However we showed that the
hypothesis of extragalactic origin of CR starting from 10^17 eV seems more
realistic.
