504 A. W. GRABAU PALEOZOIC DELTA DEPOSITS OF NORTH AMERICA 



ments from the Richmond beds of Ohio. This can not, however, be said 

 with reference to the Schenectady and Xormanskill shales, except that 

 whole individuals are wanting, and that, though better preserved in the 

 black shales, the}' are not so common as in the sandy beds. These occur- 

 rences, if any, may be considered as pointing to a marine habitat of the 

 Ordovicic Eurypterids, but even here the evidence is extremely unsatis- 

 factory. 



Lower Siluric or Magaran. — In the undoubted Lower Siluric are sev- 

 eral cases of the presence of Eurypterid remains in marine formations. 

 HalFs species of Eurypterus prominens, from the Clinton of Cayuga 

 County, New York, was described from a single cephalon, but Whiteaves' 

 E. (Tylopterus) boy lei, from the Guelph dolomites of Ontario, is a spe- 

 cies founded on a single somewhat crushed, but otherwise nearly complete, 

 individual. An unidentified species of Eurypterus is recorded from the 

 Arisaig of Nova Scotia. These occurrences are in formations containing 

 good marine faunas, but the Eurypterid is represented either by a single 

 fragment or, in the case of the Guelph beds, by a single, though nearly 

 perfect, specimen. One of the most striking occurrences of eurypterids 

 in beds referred to the Lower Siluric (Niagaran) is that in the Kokomo 

 water-limes of Indiana. This has been erroneously referred to the hori- 

 zon of the Lockport dolomite of New York, whereas it is probably of 

 Lower Monroan age, and from it four species are recorded, namely : 



1. Eurypterus ranilarva Clarke and Euedemann. 



2. E. (On ycli opt ems) Jcokomoensis Miller and Gurley. 



3. Eusarcus newlini (Claypole). 



4. Drepanopterus longicaudatus CI. and R. 



The number of specimens known of each of these species is compara- 

 tively small, but they are remarkable in showing for the most part the 

 entire individual, though the specimens are rarely perfect. From their 

 apparently macerated character and general preservation it appears that 

 we deal with exoskeletons only, and that these bodies did not live where 

 found, but were transported, though not necessarily from a distance. 



The dolomitic water-limes of Kokomo, Indiana, are highly bituminous 

 and some of the beds carry a rich brachiopod fauna, such as Conchidium 

 colleti and Wilsonia Jcokomoensis. 101 So far as known, the Eurypterids 

 are restricted to two very definite horizons, while the marine fossils occur 

 in the underlying, dividing, and overlying beds, but not in immediate 

 association with the Eurypterids. With reference to the state of preser- 

 vation of the Eurypterids, especially of Eusarcus (Eurysoma newlini) 



101 Clarke and Ruedeniann, loc. cit, p. 99, 



