398 NEW YORK STATE MUSEUM 



Rctcograptus ? eucharis Ami. Can. Rec. Sci. 1893. 5 :i 8o, 236 

 Diplograptus pristiniformis Ruedemann. Am, Jour. Sci. Ser. 1895. 



18:453. 455- %• 2 - 3 

 Diplograptus pristiniformis Wiman. Geol. Inst. Upsala. Bui. 1895. 



v. 2, pt 2, p. 69. 71, fig. 2, 3 

 Diplograptus ruedemanni Gurley. Jour. Geol. 1896. 4:298, 307 

 Diplograptus ruedemanni Ruedemann. X. Y. State Geol. 14th An. Rep't. 



1897. p. 221 ft"; pi. 1, fig. 2-10; pi. 2, 3, 5 

 Diplograptus ruedemanni Tornquist. Zoolog. Centralbl. 1897. 4:5 

 Diplograptus cf. a c u 1 e a t u s Freeh. Roemer & Freeh. Lethaea Pal. 



1897. x ^32 ; pi. A, fig. 2 

 Diplograptus ruedemanni et spinulosus (uodi. mid. 1 Ruedemann. 



N. Y. State Mus. Bui. 42. 1901. p-523 ft" 



Description. Colony small (average diameter 15 mm, but sometimes 

 attaining the double size) forming a synrhabdosome composed of the central 

 parts and an indefinite number of rhabdosomes (upward of 20 in fairly 

 complete specimens). Rhabdosomes 7 to 10 mm long, of nearly uniform, 

 width (1.5-2 mm wide according to the direction of compression). Sicula 

 minute (.8 mm), provided with a needle-shaped virgella. Thecae closely 

 arranged (16-20 in 10 mm, 40-50 in 1 inch) straight, short (1 mm long) 

 and broad (twice as long as wide) and little inclined (angle of inclination 

 of thecae 40"). Aperture straight, normal to axis of theca, furnished with 

 one (or two ?) long, straight or recurving spines. Nemacaulus thin, straight 

 and mostly short, but such twice the length of the rhabdosome have also 

 been observed. 



Position and localities. The types of this species came from the Utica 

 shale of Lake St John. Ami records it also from the Utica shale of the 

 Montmorency river, Quebec, and of St Helen's island near Montreal. 



The present writer has observed it in considerable number in various 

 outcrops of the Utica shale in the Mohawk and Hudson valleys, the most 

 notable of which are those on the East Canada creek near Dolgeville, Rural 

 cemetery near Albany, west bank of the Hudson river above Waterford 

 and at Mechanicville. It has also been noticed in the shales transitional 

 from the Trenton to the Utica bods at Panton on the east shore of Lake 



