CAMBRIAN FAUNAS. 115 
is situated about two-fifths the length of the glabella from the an- 
terior end, the others being arranged nearly equidistantly from each 
other; the posterior or occipital furrow is usually the most pro- 
nounced, sometimes being almost continuous across the glabella. The 
eye-lobes are level with the glabella and are separated from it by the 
rather broad, dorsal furrow. The eyes are elongate, narrowly cres- 
centic in outline, reaching nearly to the posterior margin of the head, 
with their anterior extremities opposite the anterior, lateral lobes of 
the glabella. The cheeks slope away from the glabella and the eyes, 
to the laterial and anterior margins, with a gentle convexity at first, 
but becoming slightly concave near the margin. The margin bordered 
by a narrow, scarcely-elevated rim, which is produced at the genal 
angles into short, rounded spines. Thorax and pygidium not seen. 
The dimensions of an average specimen are: length of head along 
axis, 8 mm.; width of head, 13.5 mm. The length of one of the 
largest heads observed is 22 mm. 
Remarks.—This species has been found most abundantly in the 
.Hardyston quartzite near Franklin Furnace, but it also occurs 
in the same formation, near Andover, near. Oxford Furnace 
and at Washington, as well as in the Green Pond region, north- 
east of Newfoundland. No complete individuals have been seen, 
the portions found usually being more or less perfect heads. 
Associated with the heads are the fragments of thorasic seg- 
ments, which doubtless belong to the same species, but no pygi- 
dium or posterior spine has been observed. Because of our lack 
of knowledge of the posterior extremity of this trilobite, it is not 
possible to identify it with absolute certainty as O. thompsoni, but 
the characters of the head seem to be identical with that species, 
although the specimens are much smaller, as a rule, than the more 
typical representatives of the species from Vermont. 
OLENELLUS? sp. undet. 
Plate III., Fig. 8. 
Among the specimens collected at Newton is a single imperfect 
free cheek of a trilobite, with an exceedingly elongate eye-lobe, which 
strongly suggests the genus Olenellus. It resembles more closely the 
similar cheeks of undoubted Olenellus from the Hardyston quartzite 
