NOTES OX PALEOZOIC CRUSTACEANS 99 



2474 Eavine east of South Otselic, Chenango co.; base of ex- 

 posed section. 



2478 Pharsalia Hook, Chenango co.; small ravine west of the 



Tillage. 

 2480 Burdick Settlement, Chenango co.; ravine one mile south- 

 east by road to South Otselic. 



2479 Hakes ravine one mile north of Pitcher, Chenango co. 

 2507 Cincinnatus, Cortland co.; small outcrop one and one half 



miles southwest of village, by side of railroad, 80 feet 

 above river. 



2451 xllong the bed of Canasawacta creek in the village of Nor- 

 wich, Chenango co. 



2511 Buttermilk falls ravine near Phelps crossing, three miles 

 north of South New Berlin, Chenango co. Base of Ithaca 

 at top of lower falls. 



2582 One quarter mile south of Deruyter, Madison co. 



At only two of these localities however have the fossils proved 

 abundant. At Laurens and in the vicinity of Noblesville certain 

 layers of the sandy shales have been found crowded with 

 Echinocaris punctata and Rhino caris colum- 

 b i n a, neither evincing any distinguishable difference from the 

 Hamilton forms. 



The gregarious habit of these Crustacea is well exemplified by 

 these occurrences, but in every recorded instance they are found 

 in a true marine fauna. 



These recurrent species, appearing at horizons above the sum- 

 mit of the Hamilton beds and the horizon of the Tully limestone, 

 have added some significant details to our knowledge of these 

 organisms, specially those of the genera Ehinocaris and 

 Mesothyra. 



Rh i n c a r i s represents a peculiar type of phyllocarid struc- 

 ture, in which the two lateral pieces or valves are hinged by sym- 

 physis with an elongated, median lance plate. The valves are in 

 actual contact only at a single point at or just back of the nuchal 

 furrow, where one overlaps and probably interlocks with the other 

 in two minute triangular flanges. This latter is the structure 



