Article: 'Hystrichospheres' (acritarchs) and spores of the Wenlock Shales (Silurian) of Wenlock, England
In the examination of twenty-five assemblages obtained from samples from the Wenlock Shales of Wenlock, several thousands of 'hystrichospheres' (acritarchs) and about 100 spores were found. These are allocated to sixteen genera and over sixty-five species and varieties are recognized. The restricted ranges of some of the species and the marked variation in the proportion of others present allow these assemblages to be grouped into three main types. One assemblage type is confined to the Lower Wenlock Shales (Buildwas Beds), one to the Middle Wenlock Shales (Coalbrookdale Beds), and one to the Upper Wenlock Shales (uppermost Coal-brookdale and Tickhill Beds).