Continuation of a description of the Hecla Hoek strata in Ny Friesland, giving the results of Cambridge expeditions to Spitsbergen; deals with the upper middle Hecla Hoek rocks of late Precambrian age. The succession consists of the lower and upper Grusdievbreen limestones, comprising ten unnamed members, and the Akademikerbreen series, comprising four formations of limestones, dolomites, conglomerates, and oolites. The wide variety of lithology and color provides the means for reliable correlations.