SPONGES AND CHANCELLORIIDS FROM THE CAMBRIAN OF WESTERN ARGENTINA

Anthaspidellid sponges are reported from the La Laji Formation in the Chica de Zonda Range in the Precordillera Oriental, Argentina. These a re generically unidentifiable fragments of crabs and more or less well -defined dendroclone spicules. They occur as skeletal elements in smal l transported fragment and are the only Cambrian occurrence of anthasp idellids known thus far from South America. Walcott (1920) proposed to include an array of dissociated spicules, including triradiate prodia enes, hexactines, and probable monactine spicules, in the genus Kiweti nokia. Assemblages tentatively identified as Kiwetinokia utahensis? Wa lcott, 1920, are reported from the Estancia San Martin Formation, of l atest Earl, Cambrian and early Middle Cambrian age from San Isidro Gul ch near Mendoza. Similar spicule assemblages occur in the La Laja Form ation from the Chica de Zonda Range, in the Precordillera Oriental nea r San Juan, and in the Los Sombreros Formation in the Tontal Range of the Precordillera Occidental-Sclerites of the sponge-like Chancelloria eros Walcott, 1920, are described from the upper Lower to lower Middl e Cambrian La Laja Formation. Chancelloria sclerites are also reported here from rocks of the Middle Cambrian Glossopleura Zone in the San I sidro Formation in Empozada Gulch in the San Isidro area of the Precor dillera Austral, west of Mendoza, in Mendoza Province. Sponges and cha ncelloriids from the Cambrian of Argentina are known basically from di ssociated skeletal elements.