  By analyzing the in-plane field magnetoconductivity, zero field transport,
and thermodynamic spin magnetization in 2D correlated electron system in high
mobility Si-MOS samples, we have revealed a novel high energy scale $T^*$,
beyond the Fermi energy. In magnetoconductivity, we found a sharp onset of the
novel regime $\delta \sigma(B,T) \propto (B/T)^2$ above a density dependent
temperature $T_{\rm kink}(n)$, the high-energy behavior that "mimics" the
low-temperature diffusive interaction regime. The zero field resistivity
temperature dependence exhibits an inflection point $T_{\rm infl}$. In
thermodynamic magnetization, the weak field spin susceptibility per electron,
$\partial \chi /\partial n$ changes sign at $T_{dM/d n}$. All three notable
temperatures, $T_{\rm kink}$, $T_{\rm infl}$, and $T_{d M/ d n}$, behave
critically $\propto (n-n_c)$, are close to each other, and are intrinsic to
high mobility samples only; we therefore associate them with a novel energy
scale $T^*$ caused by interactions in the 2DE system.
