We report the first observation of two charmed strange baryons that decay into Lambda K-+(c)-pi(+). The broader of the two states is measured to have a mass of 2978.5 +/- 2.1 +/- 2.0 MeV/c(2) and a width of 43.5 +/- 7.5 +/- 7.0 MeV/c(2). The mass and widt