A NEW GENUS OF CAMBRIAN TRILOBITES. 
37 
Movable cheek narrow, area somewhat wider than the 
fold; at the genal angle is along spine directed backward. 
Thorax, only detached joints are known, the pleura is flat 
with a diagonal furrow extending part of its length. 
Pygidium unknown. 
Sculpture . The area in front of the glabella and ocular 
fillet is covered with forked and anastomosing raised lines, 
running toward the anterior marginal fold, and the fixed 
cheek is decorated with similar lines running from the poster- 
ior inner corner, forward and outward. The whole surface of 
the crust is covered with minute tubercles, visible only with 
the aid of a lens. 
Size . Length of the middle piece of the head 21 mm. 
Width at the front 21 mm., at the eyelobe 27 mm. 
Horizon and Locality. In purple streaked grey sandstones 
of Assise 3 in Band b. of Division 1, at Hanford Brook, St. 
Martins. 
This species differs from the preceding in the longer, 
larger, more cylindrical glabella; the narrower, flatter fixed 
cheek, etc. 
The following section of Band b. of the Acadian Division 
1, of the St. John group will show the stratigraphical position 
of the genus Protolenus ; all the horizons herein named being 
below the Paradoxides beds. 
No. 5. Twenty feet. No trilobite known. The fauna consists chiefly 
of Brachiopods— Acrothele, Lingulella, etc. 
No. 4. Twenty feet. No trilobites. Ostacods of the genus Beyrichona. 
No. 3. Thirty feet. Several genera of trilobites — Ellipsocephalus, two 
or more species, Protolenus (P. paradoxoides,) Conocepbal- 
ites, etc. This is specially the zone of Ellipsocephalus. 
No. 2. Fifty feet. In the upper part an Ellipsocephalus different from 
those in Assise 3 occurs in company with Protolenus ( P. 
elegans.) The middle of this assise is specially the home 
of Protolenus (P. elegans) where it is found plentifully with 
Beyrichona tinea. The lower half of the assise has yield- 
no trilobites but contains Acrothele and other brachiopods. 
No. 1. Forty feet. In this coarse sediment the fossils are fragmentary 
and poorly preserved. Nevertheless a trilobite has been 
recognized in it, (an Ellipsocephalus ?) represented only by 
a fragment of the head-shield. The ostracod, Hipponoiharion 
Eos , is confined to this assise, and brachiopods of the genera 
Acrothele, Acrotreta, Linnarssonia and Lingulella have 
been found. 
