BULL. GEOL. SOC. AM. 



VOL. 12, 1900. PL. 18 



— 'I'Vl-KS iiF SaM) (.'HVSTAI.; 





cifosKN TO ii.i.rsiHATi: Lamination 



fffm. 



I 







I' 



:■,■ ^ t:' ■■..4 



■V'iii'?^ 



5 6 .^■-^1^>^^^^=%^j:i^^ 



FlOUKK 2.-SKKTCHKS OF TVi-KAr, SaND CuVSTAI.S, SUOWINK FArKS AKUANGKD IN PaIUS 



LAMINATION. GR3<=S MINUTE STRUCTURE 



