“Unit composed of a wide variety of mafic and intermediate volcanic and intrusive rocks including basalt, andesite, diabase, gabbro, and volcaniclastic rocks that are weakly metamorphosed to prehnite-pumpellyite and locally to greenschist facies assemblages. The volcanic and intrusive rocks are interbedded with varicolored radiolarian chert, chert breccia, chert pebble conglomerate, argillite, graywacke, and small limestone bodies. The chert, argillite, graywacke, and limestone are locally metamorphosed to metachert, slate, pelitic schist and marble” (Patton and others, 2006). Unit contains locally abundant Mississippian to Triassic fossils, chiefly from scattered limestone bodies in southwestern Holy Cross and northwestern Russian Mission quadrangles. Unit may also include rocks that probably represent unit KJiv, elsewhere mapped separately and known to contain mollusks of Early Cretaceous (Hauterivian and Valanginian) age. “A small body of amphibolite from near the northwestern border of the Russian Mission quadrangle yielded a K/Ar isotopic cooling age of 349.27±10.48 Ma” (Patton and others, 2006). This unit is located in one of the least-mapped parts of the state and has only been mapped at a reconnaissance level. It primarily occurs in fault blocks surrounded by younger rock units