  We report spatially resolved measurements of the oblique merging of two
supersonic laboratory plasma jets. The jets are formed and launched by
pulsed-power-driven railguns using injected argon, and have electron density
$\sim 10^{14}$ cm$^{-3}$, electron temperature $\approx 1.4$ eV, ionization
fraction near unity, and velocity $\approx 40$ km/s just prior to merging. The
jet merging produces a few-cm-thick stagnation layer, as observed in both
fast-framing camera images and multi-chord interferometer data, consistent with
collisional shock formation [E. C. Merritt et al., Phys. Rev. Lett. {\bf 111},
085003 (2013)].
