GLOSSARY. 



Rockford limestone (Goniatite lime- 

 stone) — basal Mississippic of In- 

 diana. 



Rockwood formation — Niagaran of the 

 Appalachians. 



Rogersville shale — middle Cambric of 

 the southern Appalachians. 



Rome formation — lower Cambric of the 

 southern Appalachians. 



Romney formation — middle Devonic of 

 Maryland, etc. 



Rondout waterline — upper Siluric of 

 eastern North America. 



Root — in crinoids, the expanded basal 

 portion of the stem, used for fixation 

 only (see Fig. 1895). 



Rosendale waterlime — upper Siluric of 

 eastern North America. 



Rostrum — a beak. In ammonites, the 

 projection of the ventral (outer) por- 

 tion of the living chamber anteriorly ; 

 in Belemnoidea, the guard ; in trilo- 

 bites the spine terminating the gla- 

 bella anteriorly (Ampyx) (see Figs. 

 1548, 1550) ; in Balanus, that one of 

 the two unpaired plates of the fixed 

 tubular portion of the shell next to 

 the scuta. 



Rotten limestone — lower( ?) Cretacic 

 (Coloradoan?) of the Gulf region. 



Ruhideau formation — lower Ordovicic 

 of Ozark region. 



Rugose — wrinkled. 



Rutledge limestone — middle Cambric of 

 southern Appalachians. 



Saddles — forward bending portions of 

 the sutures in the shells of cephalo- 

 pods ; they point toward the aperture 

 of the shell. (See also II., 21, 23.) 



St. Anne beds — lower Ordovicic of New- 

 foundland. 



St. Clair limestone — lower Siluric of 

 Arkansas. 



5"^. Croix formation — upper Cambric of 

 the Mississippi Valley. 



St. Genevieve — upper Mississippic of 

 Mississippi Valley. 



St. Joe marble — lower-middle Mississip- 

 pic of Arkansas. 

 54 



St. John formation — a term covering 

 middle and upper Cambric, and lower 

 Ordovicic of eastern Canada. 

 St. Lawrence beds — subdivision of the 



St. Croix. 

 St. Louis limestone — middle Mississip- 

 pic of Mississippi Valley. 

 St. Mary's formation — subdivision of 



the Chesapeakean. 

 St. Piran formation — lower Cambric of 



Canadian Rockies. 

 Salem limestone — middle Mississippic 

 of Indiana (see Spergen limestone). 

 Salient — standing out prominently. 

 Salinan — general term for middle Si- 

 luric. 

 Sandia — lower Carbonic of New Mex- 

 ico. 

 San Diego formation — lower Pliocenic 



of Pacific coast. 

 Sandsuck formation — lower Cambric of 



southern Appalachians. 

 San Fernando formation — lower Oligo- 



cenic of Trinidad. 

 San Lorenzo formation — Oligocenic of 



Pacific coast. 

 San Pablo formation — upper Miocenic 



of Pacific coast. 

 Santa Margarita formation — upper Mio- 

 cenic of Pacific coast. 

 Saratoga formation, Saratogan — gen- 

 eral term for the highest upper Cam- 

 bric ; also often used for the entire 

 upper Cambric. 

 Sawatch quartzite — upper Cambric of 



western Colorado. 

 Scabrous — rough or harsh, with little 



projecting points. 

 Scalce — small transverse plates in the 

 genus Unitrypa of the Bryozoa, con- 

 necting the expanded summits of the 

 carinae (see Fig. 202, g). 

 Scalariform — stair- or ladder-shaped. 

 Scarboro formation — Pleistocenic of 



Canada. 

 Schaghticoke shale — uppermost Cam- 

 bric of eastern New York.- 

 Schizochroal — in trilobites, that type of 

 compound eye in which each facet has 

 a separate covering, as in Phacops. 



