842 AxN'ALs or the Caknhgik Museum. 



over a wide geographical range and through a considerable thickness 

 of rock, they do not occur with any of the larger individuals in such 

 a way as to suggest that they are the young of any particular species. 

 Owing to the wide distribution, it becomes necessary to have some 

 way of designating them, and they may therefore be called sjjecies 

 alf^ha, beta and gai)uua. The third of these little trilobites is a single 

 specimen and is introduced merely on account of its unique form. 



Descriptions 

 Asaphus, species alpha. (Plate 12, figure 8.) 



Pygidium very small, probably representing an immature stage. 

 Axis very convex, and extends back onto the border. There are six 

 to ten annulations on the axis, the annulations being distinct to 

 the posterior end. The y>leura show five ribs on each side, each rib 

 bearing a deeply impressed line. Border narrow and smooth. 



MeasurcDieuts. — A pygidium: length 1.25 mm.; width 1.5 mm.; 

 width of axis .5 mm. .\ larger one is 2.5 mm. long, 4 mm. wide and 

 the axis is i mm. wide. 



Localify. — Especially numerous in the lower part of the Chazy at 

 the south end of Valcour Island. Found also at Crown Point, Val- 

 cour and Plattsburgh, New York. 



Asaphus, species beta. (Plate 12, figure 9.) 

 Pygidium broadly rounded, with a narrow, depressed border. Axis 

 high, extending back to the border. Faint annulations are observable 

 on the axis and there are traces of ribs on the pleura. 



Measurciuents. — A fair-sized pygidium is 4 mm. long, 7.5 mm. 

 wide; the axis is 3.25 mm. long and 2 mm. wide on the anterior 

 margin. Another pygidium : length 3.25 mm.; width 5 mm. 



Localify. — Most numerous in the middle layers at Crown Point. 

 Found also at various localities on Valcour Island, Plattsburgh and 

 Chazy, New York. 



Asaphus? species gamma. (Plate 12, figure 10.) 

 Pygidium very broad, with high, annulated, and very narrow, axis, 



but no border. The axis extends well back, but not so far as in 



species al/^lia. There are about six annulations on the axis and five 



pairs of ungrooved ribs on the pleura. 



Measiurtnents. — Pygidium i mm. long, 2.5 mm. wide. Axis .75. 



mm. long, .25 mm. wide at the anterior margin. 



