'ruii.or.iTF.s OK rni<; Chazy Limestone. 335 



Neck furrow wide and deep, extending to the genal angles. Neck 

 segment wide and convex, with a small tubercle close to the furrow. 



Free cheeks small, extending only to the front of the eyes, strongly 

 striated, (lenal angles extended into small, short spines. Eyes very 

 large, extending from the neck furrow around almost to the front of 

 the glabella. Lenses very fine and very numerous. 



Thorax. — No specimen in the collection shows the total number 

 of thoracic segments, and the largest number on any fragment is eight. 

 The median lobe is very wide toward the front, but tapers rapidly. 

 The segments are beautifully adapted for rolling up, having a 

 very neat interlocking devise. At the sides of each segment are 

 fulcral nodes, and processes which fit over the segment ahead and 

 against its fulcral projection. The side lobes of the segments are 

 short, obli(]uely furrowed, and turn back at angles of from 30° to 45°, 

 the posterior ones turning back most sharply. The pygidium is small, 

 and divided into four lobes which extend back as spines. On the 

 anterior edge are two nodes similar to those on the thoracic 

 segments. There are two large projections on the surface of the 

 pygidium, and each is divided by a diagonal impressed line. 



The following are the measurements of a couple of heads. An 

 average cephalon : length 9.5 mm. ; width 11 mm. ; width of glabella 

 at widest part 8 mm.; at anterior ends of eyes 5 mm. A larger ceph- 

 alon is 12.5 mm. long, 16 mm. wide, and the greatest width of the 

 glabella is 1 1 mm. 



Locality. — Found in the middle Chazy on the east side of Valcour 

 Island, New York, and also at Chazy. The figured specimens are 

 from Smugglers Bay, Valcour Island. 



Family ASAPHID^-F Emmrich. 



Genus BATHYURUS Billings. 



Bathyurus angelini Billings. (Plate 10, figures 11, 12.) 



Paradoxide; Logan, 1852, (Quarterly Journal of the (Geological Society of London, 



volume VIII, page 207. (Identified by Salter.) 

 Aidphns (or O/c'iius) Salter, 1859, Quarterly Journal of the (Geological Society of 



London, Volume XV, page 555, figures 3, 4. 

 Bathyurus Angeli)ii Billings, 1859, Canadian Naturalist and (Geologist, \'olume I\', 



page 467, figure 37. 



This trilobite was described by Billings from the ('hazy at Grenville, 



