368 NKW YORK STATi: MUSEUM 



iK-tahodron — crystnl form with oiulit ('<iii;il fncos, oncli nn oq\iilnttM':il ti'i- 



aiiirle 

 old Innd — that jxirtioii (tf land hcliind (lie constal jilain which su|i|tli»'d tho 



iiiatorial <»f which the strata of the coastal plains wcri' formed 

 orthid — resembling or related to the hrachioi>od Oi-this 

 orthoeeraeone — a straight oonelike shell like that of Orthoceras 

 orthoeoratites — belonging or relatinl to the genus Orthoctras 

 outeroi) — intersection of rock mass with the surface 

 outlier — erosion renjnant left in a valley at a distauct' from the plateau 



or upland with which it was previously continuous 

 ostracods — a group of marine crustaeea generally nnnute, inclosed in a 



bivalve shell which does not show concentric lines of growtii 

 overlap — extending beyond an underlying stratum 



pedicle valve — that valve, generally the larger, of the brachioi» )d shell 

 which gives emission to the pedicle or supporting organ. This valve 

 also contains the teeth by which the hinging of the \alves is accom- 

 plished 



pelecypods — the class of bi\alve mollusk or lamellibranchs to which the 

 clam belongs 



penei)lain — the nearly level surface, almost a plain, resulting from the 

 erosion of an uplifted region by subaerial agents, to a condition 

 approaching sea level 



pentameroid — related to the genus L'entamerus amcng the brachiopods 



periphery — the margin of the circmnference 



pervious — penetrable by water 



petalite — a complex silicate of alunnnnm with sodium, potassium or lith- 

 ium 



plications — folds or flutings 



posterior — pertaining to the hinder end 



prenuncial — amiouncing beforehand, heralding the coming of 



protuberant — in-ojecting outwards 



pteropods — a class of marine mollusks floating on the surface of the water 

 and having delicate generally transparent shells, needlelike in the 

 commonest forms 



punctate — marked by spots or shallow pits 



pustules — small elevations or tubercles 



pustulose — covered with pustules 



pygidinm — the posterior portion of the body of the trilobite. erroneously 

 called tail 



pyrite — the mineral form of bisullid of iron Fo S2 



pyritiferous — containing or beai-iiig jiyrite 



pyritohedron — the ])entagonal dodecahedi-on (which s(H') a form connnonly 

 assnnuHl by pyrite crystals 



quartz — the mineral form of oxid of silicon (SiOz) 



<piart/ite — a rock i-esnlting through Ww metamoi-phic change of a (piartz 



sandstone, the (juarl/ gi'ains become closely united by a paste or 



iii.'ih'ix of (juarlz 



radii — radiating lines, such as ar(> found on the surfaces of many shells 

 revived stream — streams icsuniing activity owing to elevation or other 

 causes 



