The two remaining species described come from eastern Cape Breton from a higher horizon. One is the carapace of a species of Eurypterid whose near allies have been found at an equivalent horizon in Pennsylvania, and in England. The présence of Eurypterids, a rapidly declining race, in Nova Scotia, had already been indicated by the previous discovery of several fragmentary abdominal remains. The other form under consideration is an odd one of doubtful relationships, but which invites comparison with such shield bearing Merostomata as the Xiphosurids or sword-tails.
Phylum Charophyta
Genus Palaeochara
Palaeochara n. g.—Oogonium like Chara, but with six, instead of five spirally wound investing cells. Genotype Palaeochara acadica.
Palaeochara acadica n. sp.
Description: Oogonium subglobular to pear-shaped with hemispherical base and conical apex. Length somewhat exceeding the greatest diameter. Investing cells six in number, commencing around a smooth, circular, basal area and making one cpmplete spiral turn to the raised conical end. Six or seven spiral ridges visible on a side view. Length 0.55 mm.; diameter 0.53 mm.; diameter of smooth basal area 0.075 mm.
Locality: St. Rose mine, Inverness county, N.S.
Horizon: Coal Measures.
Remarks: The remains of the oogonium are now preserved as iron pyrites, inferred to be a pseudomorph after calcite. Thin sections examined under reflected light clearly show the Chara affinities of the fossil in that the oogonial investment consists of partial infillings of former spirally wound elongate cells. The position of the former walls of these cells is revealed in section either as oblique or transverse lines of parting, and in surface view by narrow grooves on the spiral ridges. The latter appearance of the surface indicates that the original calcareous deposit grew from initial deposition against the concave inner borders of the cells as in recent Chara. In recent Charas the lateral walls break down as the fruit matures, so that a continuous shell of lime finally surrounds the oospore. In Palaeochara the lateral walls evidently persisted to a greater extent. The interior of the oogonium is now filled with infiltrated calcite. The basal circular area from which the spirals spring is a sunken pit, or foramen, and probably indicates the former position of attachment of the stalk cell.
