13 



extending more or less beyond the distal cells. Serratures, or cells, about 

 twelve in the length of a centimeter. 



Extreme width of the stipe between the mucronate points of each 

 side often less than two millimeters and seldom more ; length of stijje, 

 from one to three centimeters. 



Position and locality. — Shales (probably of the age of those at Nor- 

 mans Kill, near Albany, New York), five miles north of Belmont, Nevada, 

 where it is associated with the two following species. 



Graptolithus quardrimucroxatus Hall ! — Stipe quadrilateral ; 

 section oblong, gradually but slightly increasing in transverse diame- 

 ter from the proximal or basal end to about midlength, where the 

 maximum size is reached ; cells opening on the two narrower sides ; their 

 apertures directed obliquely upward, narrow, transverse, like four-sided 

 slits, of uniform size, about half the width of the interspaces, their length 

 nearly equaling the full short diameter of the stipe. At each of the two 

 outer corners of each cell-aperture, a mucronate point projects, which, 

 together with the slight projection of the cell itself from the body of the 

 stipe, gives the latter a doubly-serrated appearance, when viewed upou 

 one of its broader sides, like that of two stipes of an ordinary Diplograp- 

 tus compressed together. A slender, thread-like axis, ])assiii^ longitudi- 

 nally through the middle of the stipe, usually appears as a part of the 

 imprint of the specimens upon the shale. 



This species, so far as can be determined from the specimens, is so 

 closely like G. quadrimucronatus Hall, from the " Utica-slate formation, 

 Lake St. John, east of Blue Point," tliat it is referred provisionally to 

 that species. In case more perfect specimens should show the sjiecies 

 to be new, as it probably is, I propose for it the name of O. Behnon- 

 tensis. 



Position and locality. — Shales (probably of the age of those at Nor- 

 man's Hill, near Albany, New York), five miles north of Belmont, Ne- 

 vada, where it is associated with the last-described species, and also 

 with the following one. 



Graptolithus (Climacograptus ?) ramulus (sp. noi\) Stipe slen- 

 der, bifurcating, bearing cells upon both edges below the bifurcation, and 

 upon only one edge, the outer, above that point, so that each series of 

 cells is continuous from the common proximal to the two distal extrem- 

 ities respectively, and, of course, occupy" the outer edges of the branches 

 only. The bod}- of the stipe throughout is moderately thin and flat; but, 

 judging from the presence of a little pit in the shale at the place of each 

 cell, the latter were inflated in form, so that their transverse diameter 

 was considerably greater than the thickness of the stipe. Cells moder- 

 ately large, each bearing upon its outer wall, just below the aperture, a 

 slender, outward-projecting spine. 



This species has almost exactly the general aspect of G. ramosus Hall, 

 from the dark shales at Norman's Kill, near Albany, N. Y.. and was 

 at first regarded as identical with it; but, on close inspection, it is found 

 to differ materially in the form of its cells and the character of the stipe. 

 Some of these ditierences seem also to modify its relations to the sub- 

 genus Climacograptus, to which G. ramosus is assigned by Professor Hall, 

 the author of the subgenus. 



Position and locality. — Shales (probably of the age of those at Nor- 

 man's Kill, near Albany, N. Y.), five miles north of Belmont, Nevada, 

 where it is associated with the two species last described. 



Besides the foregoing species of Graptolites, which are referred with 

 some doubt to the Trenton period as defined by Dana, other localities 



