NEW SPECIES OF CAMBRIAN FOSSILS FROM CAPE BRETON. 275 > 
layers are freely intermingled with small lumps and particles of 
calcium phosphate. The phosphate lumps are frequently moulded on 
the shells, or entirely enclose them ; though some shells are enclosed 
■ in the phosphate, others are free, and with fragmentary shells are' 
mingled with the sand. Other masses of the phosphate are entirely 
free of the shells, and are smooth and shining, as though rolled on the 
beach ; yet the flat, oval, or rod-like pieces of the phosphate seem the 
natural form which the substance assumed when in a gelatinous 
condition. Probably the formation of the phosphate was co-temporary 
with the entombment of the shells. 
It seems doubtful if this species was at all near the recent Lingula 
in structure, yet it appears to be no nearer to Lingulella or Obelus : 
it is therefore left provisionally in the first named genus. 
In its outline it is like L. Covingtonensis, H. & W., of the Lorraine 
Shales of Ohio.* 
Acrotreta bisecta, n. sp. PI. V, figs. ba-g. 
Shell substance thin, calcareo-corneous. Outline of the valves,, 
oblately circular. 
Ventral valve elevated conical. Height about one-quarter less tban> 
the width. The umbo is about a quarter of the length of the valve from 
the posterior margin. The valve is somewhat flattened on the posterior 
slope at the cardinal area, which is nearly as long as half the width of 
the valve, and has a deltidial area, bounded by distinct furrows ; else- 
where the valve slopes regularly to the margin. Interior . — The mould 
is always truncated and has a somewhat convex summit; in some 
examples there are traces of one or two diaphragms extending across- 
or over this part of the valve, from the anterior slope. A oreseent- 
like ridge extends around the back of the summit of the mould and, 
down the lateral slopes. Towards the front of the valve a pair of low 
ridges radiate toward the front of the mould, but fade out at one- 
quarter from the anterior margin. 
The dorsal valve is most convex at the back, where the slope is 
nearly vertical ; it has a long flattened slope to the front. Interior . — 
The mould of this species is marked by a long, deep, narrow furrow 
(indicating a strong mesian ridge); this is somewhat broader in the* 
anterior third than elsewhere ; the mould also has two pairs of pits-. 
* N. York State Geologist’s Report, 1891, Hall & Clarke, pi. i, fig 7. 
