Twee nieuwe sponzensoorten als zwerfsteen in Nederland : Chiastoclonella sp. en Syltispongia ingemariae. - rectificatie G&H

Among the thousands of erratic silicified sponges from sandpits with lower pleistocene fluvial arenacious deposits in the Dutch-German borderregion two species of ordovician chiastoclonellid sponges have been recognised. The author reports the occurrence of 9 specimens of Chiastoclonella sp. RAUFF 1895 and of 14 specimens of Syltispongia ingemariae VAN KEMPEN 1990. Most specimens in private collections have been collected already many years ago, but went unrecognised until now. The author expects more reports from collectors as a result of this paper.