GEOLOGY AND PALEONTOLOGY OF THE SCHOHARIE VALLEY 369 



rhynchonelloid — related to or resembling the brachiopod genus Rhyn- 

 chonella 



ripple marks — wavelike elevations formed in sand or mud in shallow 



water or by wind on drifting sand 

 rostral cavity — cavity under the beak of bivalve mollusks or brachiopods 

 rubble — coarse broken rock material 

 rudaceous — consisting of coarse fragments ; rubbly 

 rugose — rough surfaced 



saddle — in ammonites the forward bending portion of the suture line i. e. 



bending towards the aperture 

 scutella — a shield ; flattened shieldlike remains of crinoids 

 septa — the radiating plates in the cup of a coral 



septum — a supporting bracket in brachiopod shells ; one of the septa of a 



coral _ 

 shearing — cutting and displacement along the cut plain by violent means 

 silicious — composed of or containing silica 

 sinistral — left-handed 



sinus — a median depression on the brachiopod shell, generally the pedicle 

 valve 



siphonal lobe — the lobe in the suture of the goniatite or ammonite shell 



which passes over the siphuncle 

 siphuncle — the tube passing through all the septa of the shells of cephalo- 



pods 



slickensides — a smooth striated surface — commonly coated with mineral 

 matter, resulting from the friction produced by two rock masses sliding 

 past each other 



spar — a general term applied to minerals cleaving with smooth surfaces 

 spar, heavy — barite 



spar, nail head — the flat form of calcite crystals 

 spar, satin — fibrous gypsum 



stalactite — pendant structures of calcium carbonate or other minerals de- 

 posited on the roofs of caves, etc. 



stalagmite — the structure on the floor of the cave corresponding to and 

 growing up to meet the stalactite 



stratigraphic — pertaining to the strata or the science of the strata 

 (stratigraphy) 



stratum — the bed of rock composed throughout of the same material or 

 texture 



striae — fine lines or markings such as occur on the surfaces of shells, etc. 

 strontianite — the mineral form of carbonate of strontium 

 strontium — one of the earth-alkaline elements 



strophomenoid — resembling or related to the brachiopod genus Strophomena 

 subcylindric — approaching to, but not attaining, the cylindric form 

 suborbicular — approaching a spheric form 

 sub] icnt agonal — approaching a pentagonal or five-Sided form 

 subquadrangular — approaching a four-sided or quadrangular form 

 subrectangular — approaching a right angle 



subsequent stream — the stream which cuts out the inner lowland between 

 the cuesta front and the old land 



