214 



Ft. In. 

 22 — Limestone, with top of layer composed of immense numbers of 



Zygospira modesta 3 



21 — Rather coarse shale 2 



20 — Lumpy, shaly limestone. Asaphus, Rapnrsqnina 3 



19 — ^Coarse to fine-grained barren limestone 8 



18 — Lumpy, shaly limestone. Eafinesquina (aa), Trilobites (a), Zygo- 

 spira, Streptelasma, Bryozoa 12 



17 — Limestone, with Rafineaquina, Zygospira (aa), Bryozoa, Oithoceras. 5 10 



16 — Shale, with thin layers of limestone 1 



15 — Very compact, fine-grained blue barren limestone 6 



14— Shale 8 



13 — Compact limestone. Calymene, Zygoapira, etc 5 



12 — Limestone. Calymene (aa), Bryozoa, Rafinesquina, Orthoceras .... 1 3 



11 — Shale, with thin layers of limestone 3 8 



10 — Thin argillaceous limestone with Calymene and Bryozoa (a) 1 



9 — Massive blue limestone. Rafinesquina, Trilobites, Bryozoa 7 



8 — Limestone. Rafinesquina, Zygospira, Bryozoa 2 9 



7 — Thin argillaceous yellow-spotted limestone. Rlatystrophia, Heber- 



tella. Rafinesquina, Bryozoa 1 



6 — Limestone. Heberte'la {a.a,), Rafinesquina 7iasuta, Flat ysntrophia lynx. 1 2 



5 — Bryozoal limestone 4 



4 — Covered, probably ^hale 1 



3 — Limestone with Trilobites, Zygospira, etc 2 



2 — Coarse crystalline limestone. Hebertella 6 



1 — Covered to river level 62 



Total section 3-57 



Number 7 of this section represents the top of the Platystrophia zone. At 

 Vevay the top of the same zone is 358 feet above river level, and at Lawrenceburg 

 about 390 feet. The Madison section afibrds an excellent opportunity to study 

 the upper Ra(ines(|uina zone. It is in the upper zone that this fossil is so con- 

 stantly associated with Zygospira modesta and a number of species of Lamel- 

 libranchs. In the lower zone it has no such constant associates. 



Section along Clifty creek (§ 1.12 B) : 



. Ft. In. 

 22 — Limestone. Rnfinesquina, Lamellibranchiata, Gastropoda, Crin- 



oids 6 



21 — Limestone and coarse lumpy shale. 7 4 



20— Shale and limestone. Top, a heavy layer of limestone with con- 

 spicuous wave-like markings 21 4 



19 — Partly covered, but represented by heavy layers of limestone in 



the bank above 18 11 



18 — Limestone and shale 14 4 



17 — Limestone. Rafinesquina (aaa), Hebertella 5 



