NELTNERIIDAE AND HOLMIIDAE (TRILOBITA) FROM MOROCCO AND THE PROBLEM OF EARLY CAMBRIAN INTERCONTINENTAL CORRELATION

Previously undescribed Holmiidae from the Sectigena Zone of Morocco in dicate correlation of this zone with other zones bearing Holmiidae on Baltica, Avalonia, Siberia, and Laurentia. The occurrence of the young est Antatlasiinae in the Sectigena Zone and the oldest Protoleninae in the overlying Hupeolenus Zone suggests correlations of the Sectigena Zone with upper Atdabanian beds bearing the youngest Antatlasiinae and the Hupeolenus Zone with Botomian beds bearing the oldest Protolenina e in Siberia. The occurrence, in the overlying Hupeolenus and Cephalop yge Zones, of Paradoxides s.l. in association with the olenelloid Camb ropallas and with trilobites characteristic of the Lower Cambrian ''Pr otolenus'' Zone of Avalonia calls into question the major criteria for recognition of strata of Early and Middle Cambrian age. New taxa incl ude Iyouella contracta n. gen. and sp. of the Holmiidae and Bondonella sdzuyi n. sp. of the Neltneriidae. The known species of Neltneria, N. jacqueti and N. termieri, are revised.