.;<() NKW YORK STATE Ml'SKIM 



suture — llio lini' in;i(lt' liy ilic Juiiciitui of the septum with the shell iu 

 the Ceplmloiwda. \isil>l(> when ilic cMvitics of the slu'll are filled with 

 rock matter and the shell removed, the common condition seen in 

 fossils. Also tlu* line of junction hetween the coils or whorls of a 

 gastropod shell. 



talus — the accumulation of rock dehris at the foot of a cliff 



telson — the spine at the end of the tail of crustaceans 



tenuous — drawn out finely 



terehratuloid — related to or rescMuhlinc: the brachi<»p()d ijcenus Terebratula 



texture — the grain of rocks 



till — the unassorted material left by the mcltini; ice sheet of the irlacial 

 periml. It is generally full of boulders and c<)ntains much i-lay and 

 rock flour 



torticone — a twisted cone as in snail shells (gastropods) or certain cepha- 

 lopods (Trochoceras) 



tran.sgression — encroachment on, as the sea advancing over the land which 

 it submerges 



trilobate — three lobed 



trilohite — a class of Crustacea, longitudinally divisible into three parts or 

 lobes and having a head or cephalon with a central glabella, com- 

 pound eyes and lateral or free cheeks sei^arated from the rest of the 

 head by the facial sutures: a body or thorax divided into a number 

 of rings and a pygidium or abdomen consisting of a single grooved 

 piece. The class is confined to the Paleozoic rocks 



tufa, calcareous — a deposit of ])orous lime carbonate formed by certain 

 springs or streams 



tumid — sw^ollen 



umbilicus — the basal cavity in the axis of circling of gastropod and cepha- 



lopod shells 

 umbonal — pertaining to the beak or umbo of bivalve shells 

 unconformity — discordant relation of strata 

 unconformity, stratigraphic — an unconformity marked by absence of 



certain intermediate formations without discordance of strata (dis- 



conformitjO 

 unconformity, structural — a true imconformity with discordance of strata 



The first series is folded and eroded before the second is deposited [see 



text] 



venter — underside of the body. In coiled ceph-ilo])od slu^lls it is mostly the 



outside of the coil 

 ventral — pertaining to the underside of the b k'.v 

 ventricoso — bulging 

 vermes — the class of worms 

 vitreous luster — the luster of glass 



waterlime — limestone which on burning will form natural cement 

 wliorls--tlie coils of a gastrojiod or coihMl ccpbalopod shell 

 v^'ing — in coi-tain jtclccypods the posterior or largci- i)ortion of the hinge 

 region; llic anterior or smaller portion is the o;\i' 



