512 Systematic Paleontology 



" Surface grauulose, the granules being somewhat stronger on the more 

 prominent parts of the head and in front of the eyes, while on the thorax 

 and pygidium there is usually a stronger row of granules along the lower 

 margins of the articulations. The granulose marking, however, is subject 

 to considerable variation, either from accidental or other causes ; and some 

 specimens of tlie pygidium present a fine granulose texture, visible only 

 under a lens." Hall, 1859. 



Occurrence. — Helderbeeg Formation, Coeymans Member. Devil's 

 Backbone, Dawson. New Scotland Member. Devil's Backbone, Cor- 

 riganville, Dawson, Tonoloway? 



Collections. — Maryland Geological Survey, U. S. National Museum. 



[Ohern.] 



Dalmanites berkleyensis u. sp. 

 Plate XCIV 



Description. — Pygidium triangular, convex, large, its length 7/9 of 

 its width. Axis consisting of 17 articulations in type specimen, its diam- 

 eter at anterior end a little more than one-seventh width of pygidium, 

 posterior extremity one-third its anterior diameter, quite convex in middle, 

 very slightly convex, or even concave near margin ; a row of pit-like de- 

 pressions between articulations a short distance from margin on each side 

 in exfoliated specimen. Pleurse 17 in specimen observed, broad, separated 

 by deep and narrow furrows, slightly deflected baclcwards at anterior end, 

 strongly so at posterior end, where they become nearly parallel to axis. 

 Margin distinct, depressed, convex, very broad, slightly marked by furrows 

 between pleura, its distinctness and breadth not adequately shown by 

 figures. Surface not observed, probably bearing tubercles. 



Length of pygidium 170 mm. ; width 125 mm. 



This species differs from other described forms in its broad margin. It 

 is larger than any other species of the fauna. A single specimen of this 

 large and fine trilobite has been found. 



Occurrence. — Oriskany Formation, Eidgely Member. Pennsyl- 

 vania Sand Quarry 3 miles north of Berkeley Springs, West Virginia. 



Collection. — C. K. Swartz. 



[Swartz.] 



