Distribution and diagenesis of microfossils from the lower Proterozoic Duck Creek Dolomite, Western Australia.

Two distinct generations of microfossils occur in silicified carbonates from a previously undescribed locality of the Lower Proterozoic Duck Creek Dolomite, Western Australia. The earlier generation occurs in discrete organic-rich clasts and clots characterized by microquartz anhedra; it contains a variety of filamentous and coccoidal fossils in varying states of preservation. Second generation microfossils consist almost exclusively of well-preserved Gunflintia minuta filaments that drape clasts or appear to float in clear chalcedony. These filaments appear to represent an ecologically distinct assemblage that colonized a substrate containing the partially degraded remains of the first generation community. The two assemblages differ significantly in taxonomic frequency distribution from previously described Duck Creek florules. Taken together, Duck Creek microfossils exhibit a range of assemblage variability comparable to that found in other Lower Proterozoic iron formations and ferruginous carbonates. With increasing severity of post-mortem alteration, Duck Creek microfossils appear to converge morphologically on assemblages of simple microstructures described from early Archean cherts. Two new species are described: Oscillatoriopsis majuscula and O. cuboides; the former is among the largest septate filamentous fossils described from any Proterozoic formation.

Precambrian age of the Boston basin: new evidence from microfossils.

A Vendian (Late Proterozoic Z) age has been determined for the Boston Basin by comparison of a microflora from the Cambridge Argillite with other late Precambrian assemblages. The microfossils, which include Bavlinella cf. faveolata, are preserved as petrifactions in pyrite. This age designation for the sedimentary rocks of the Boston Basin should allow for the reinterpretation of the structure of the basin and its regional correlations.

Contamination of illicit phencyclidine with 1-piperidinocyclohexanecarbonitrile.

A retrospective study of illicit phencyclidine (PCP), which consisted of 94 different cases or 213 individual samples, has shown that one third of both the powder/tablets and green plant material contained the synthetic contaminant 1-piperidinocyclohexanecarbonitrile (PCC). The mole % PCC/PCP ranged from 1 to 68%. The method of analysis was gas chromatography (3% OV-7, 205 degrees C) and in preparation for analysis the sample was dissolved directly in chloroform or extracted from a strongly acidic solution (0.1 N HCl). Using these extraction conditions PCC was found not to undergo measurable decomposition.