Archean sedimentary rocks of very limited lateral extent from horizons within basaltic and ultramafic volcanic sequences at Kambalda, Western Australia, are extremely variable in major elements, LIL and ferromagnesian trace element compositions. The REE patterns are uniform and do not have negative Eu anomalies. Two samples have very low total REE abundances and positive Eu anomalies attributed to a very much greater proportion of chemically deposited siliceous material. Apart from these two samples, the Kambalda data are similar to REE abundances and patterns from Archean sedimentary rocks from Kalgoorlie, Western Australia and to average Archean sedimentary rock REE patterns. These show a fundamental distinction from post-Archean sedimentary rock REE patterns which have higher La/Yb ratios and a distinct negative Eu anomaly.