BUFFALO SOCIETY OF NATURAL SCIENCES 23 



cally undetermined Pterygotus mentioned by Billings, is from the 

 Grand Greve limestone of Lower Devonic age. Remains of Ptery- 

 gotus have also been found in the lower marine Devonic at Dalhousie. 

 Finally, near Campbellton, New Brunswick, "in some indurated 

 limestones containing fish remains of probably Upper Devonic age" 

 are also eurypterid remains which Clarke and Ruedemann have de- 

 scribed as Pterygotus atlanticus. An extremely incomplete and prob- 

 lematic form is a two-jointed fragment from the lower beds of the 

 Portage sandstones of Italy, Yates County, New York. Originally 

 described by Dawson as a plant (Equisetides wrightiana Dawson), it 

 was later placed among the eurypterids by Hall as Stylonurus (?) 

 wrightiana and is now so recognized by Clarke and Ruedemann. 

 There is but a single fragment, part of a jointed appendage apparently. 

 A number of fragments of Stylonurus, originally described as Stylo- 

 nurus excelsior by Hall and which Beecher used in making the restor- 

 ation which he called Stylonurus lacoanus, have all been united by 

 Clarke and Ruedemann under the species Stylonurus (Ctenopterus) 

 excelsior. There are only two specimens, one a complete carapace 

 from the Catskill beds at Andes, Delaware County, New York, and 

 another more fragmentary carapace from the same formation in 

 Pennsylvania. Eurypterus beecheri Hall described from the Chemung 

 of Pennsylvania has proved to be the same as Stylonurus beecheri. 



Mississlppic. From the Waverly beds of Warren, Warren County, 

 Pennsylvania, a single eurypterid was described by Hall and Clarke 

 in 1888 as Eurypteris approximatus. No complete description of this 

 form is given anywhere, but the figure in the Palaeontology of New 

 York, Volume VII, plate 27, figure 6, (106), shows the one specimen 

 that has been found in which there are the cephalon and nine somites. 

 This form is regarded by Clarke and Ruedemann as one of several 

 phylogerontic species of Eurypterus which constitute the end members 

 in different lines of development in North America and mark the 

 decline of the race. 



Carbonic. In the Carbonic (Pennsylvanic) are found four 

 species of Eurypterus in Pennsylvania; Eurypterus {Anthraconectes) 

 mazonensis Meek and Worthen (170) in the Coal Measures of Mazon 

 Creek, 111.; two species in the Carbonic of Nebraska, and two doubtful 

 species from St. John, New Brunswick. Particular attention should 

 be called to Eurypterus (Anthraconectes) mansfieldi which C. E. Hall 

 has figured (98, pi. IV), showing the form just as it was found lying 

 on ferns in a very perfect state of preservation, in the lower Productive 



