A brief description is given of a boring through the Tretaspis series and the uppermost portion of the Chasmops series in the Fågelsång district. The examined portions of the Chasmops series agree with the corresponding strata in Bornholm. The Tretaspis strata which hitherto had been almost unknown in the area consist mainly of pale mudstones and shales including black graptolitiferous layers. They exhibit remarkable similarities with the Moffat series in Scotland and the sequence from Brzezinki in Poland. The following subdivisions are distinguished (from below upwards): 1) Zone ofTretaspis granulata;2) Zone ofDicellograptus anceps;3) Practically unfossiliferous mudstones for which the termLindegård mudstoneis proposed.