24 THE HABITAT OF THE ETJRYPTERLDA 



Coal Measures in Beaver County, Pennsylvania. Eurypterus stylus 

 of Hall from the Venango beds is probably the same as E. (Anthra- 

 conectes) mansfieldi, both type specimens being compressed longitudi- 

 nally, but otherwise appearing the same. Eurypterus (Anthraconectes) 

 pennsyhanicus C. E. Hall described from a single small carapace from 

 Pithole City, Venango County, Pennsylvania is probably allied to 

 E. mansfieldi, according to Clarke and Ruedemann (39, 428). A few 

 fragments called by Hall E. ? potens also occur in Pennsylvania. 

 The Carbonic eurypterids are in productive coal beds associated with 

 plants and land animals. The fauna and flora at Mazon Creek have 

 been especially studied by Meek and Worthen (170) from whose 

 report the following associates of Eurypterus mazonensis are taken: 



A Xiphosuran Euproops danae M. and W. 



An isopod Acanthotelson stimpsoni M. and W. 

 also A. eveni M. and W. 



Decapoda: Palaeocaris typus M. and W. 



Anthrapalaemon gracilis M. and W. 



Myriopoda: Euphoberia armigera M. and W. 



Arachnida: Pulmonia: Eoscorpius carbonarius M. and W. 

 Mazonia woodiana M. and W. 

 Architarbus rotundatus Scudder 



Cock- roach: Mylacris anthracophila Scudder 

 . Other insects: Miamia danae Scudder 

 Chrestotes lapidae Scudder 

 The remains from the Coal Measures of Nebraska were found by 

 Barbour in an outcrop one mile south of Peru in the bluffs facing the 

 Missouri River (10). The formations exposed there consist of alter- 

 nating shale and limestone changing rapidly to a shale which finally 

 merges into a massive sandstone. In this last bed there occurred a 

 shaly band composed of thin, irregularly shaly layers, seldom half 

 an inch thick, alternating with micaceous sand. This whole band 

 was scarcely a foot thick and extended for over three hundred feet. 

 Even within the band it was only the topmost two inches of the shale 

 seams which yielded eurypterid remains. These were found in con- 

 siderable abundance, forty specimens so far having been obtained in 

 an area of as many square feet. The chitinous shells, probably repre- 

 senting merely the shed exoskeletons, have in all cases been reduced 

 to carbonaceous films, but except where these are very thin they are 

 in a good condition of preservation so that the grosser anatomy and 

 surface markings can be seen and even some of the minute sculpturing. 



