EXPLANATION OF PLATE VII. 



Unv.Ntii(,.M;u.A Mviti.NA •Iw4 



l'ij;.s. 1-4. Dorsal, ventral, proliln, siiul front views of a characteristic biiucimun. 

 ">. Ventral valve, showing a variation of form in the sinus. 



KlIV.NClIO.NKLL.V GNATIIOPUOKA? 'Jl^l 



Kij;- <>• View of the ventral valve referred with doubt to this species. 

 TnKKItlSATULA AUGIISTA 2iib 



Fig. 7. View of a ventral valve of the nsual form and size. 



8-10. Dorsal, ventral, and prolilo views of a spocimeu, enlargid to two dluiiieters. 



(iuvrii.KA ? Calceola var. Nehhascen.si.s ? 2M) 



Fig. 11. Interior of the larger valve, sliowing the prevailing form whiili occurs in the 

 localities mentioned under the description. 



O-STKIvA KnGKLMANNI ? OHJ, 



Fig. 1-^. View of an impression u£ llie interior of the attached valve. 



C'AMriONF.CTE.S liKLLISTHIATU.S 2S'J 



Fig. i;j. View of an imperfect right valve of the size most common among those in thecoUec- 



AVICL-LOPECTKN? (EUMICHOTLS) AUGUSTENSIS -JSS 



Fig. 14. View of a right or flat valve. 



15. A left valvo from the same speiiiiicu ut luck. 



10. Enlargement of stria) from anollur individual, preserving the siirfaeo. 



C'AMI'rO.NECTES PEUTENUISTIUATU.S V.".»l 



Fig. 17. View of a right valve of the species, eidarged to twie.'. the n;itural size ; tln^ posterior 

 wing restored in outline. 



(,' AM 1-TON ECTES EXTENUATUS •JDll 



Fig. 18. A right valve, natural size. 



NAriCA? LkLIA ■J\)ri 



Figs. VJ-21. Three views of an individual of the ordinary si/e. enlarged. I'ln- liu.' near tig. L'O 

 shows the natural height. 



TliKiONIA QL'ADKANGULARIS 'JlCi 



Fig. a-^ View of an imperfect right valve, enlargeil to twice, the n.-iinial siz.^. The outline 

 would seem to have heon considerald.v extended i)osteriorly. 

 Lima (I'i.agiostoma) occiuentali.s 'SJ'-i 



Fig. -S-i. View of a left valve, slightly restored at the beak and hinge, as also (ju the uiubone. 

 Fi;.MICROTI.S cuuta? ux'J 



Fig. 24. View of a left valve, enlarged, showing the aUoruatc size of the r.idii. 

 SEfrOCAIiDt A Caiiditoidea •,".«; 



Fig. •,'.'). View of the posterior end of the specimen ih^serilMMl. 



SEl-roCAIlDIA TYl-ICA 'SX, 



Fig. yii. Enlarged view of the exterior of a right valve, showing tlu^ general form and tin' 

 ornamentations ou the ribs. 

 •J7. View of the interior of the sam(! valves, show iiig the hinge-characlcr^ as desiniln-d. 

 •^8. Enlarged hinge-line of tin; left valve. 

 •JO. Cast of a large right valve, enlarged to twice the natural size, to show the posternu 



