NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 293 



Feet Meters 



(.9 m.), I foot, 4 inches (.4 m.) and 4 feet (1.2 m.) 



thick 8 4 2.5 



II. Thin-bedded, bluish gray limestone with shaly partings. 5 6 1.7 



i/. Limestone similar to ih 4 6 1.4 



Fauna. — Comminuted tests of small trilobites. 



ik. Similar to ii 19 5.8 



i/. Similar to ih 2 6 .8 



FaiuM: — (2iv) : 



BiUingscUa sp. 

 Agnostus 

 Conaspis sp. 

 IrvingcUa sp. 



I w. Similar to li 21 6.4 



m. This stratum is very much like that of i/i. It is com- 

 posed of three more or less irregularly-bedded layers 

 of gray limestone. The upper layer has a Stroma- 

 toporid-like structure that gives its upper side a mam- 

 millated surface, a character also shown on the upper 

 layer of i/t. Small fragments of thin layers of 

 limestone occur in places to an extent sufficient to sug- 

 gest interformational conglomerate. This and the 

 irregular arrangement of the fragments of fossils and 

 their matrix suggests strong current action. Locally 

 the limestone weathers to a yellow-buff color, which 

 indicates a magnesian content similar to that in the 



thick layers of magnesian limestone below 3 2 .9 



Fauna. — In the lower layer, near its base, a number of 

 fossils were collected (21s) : 



Billingsella sp. 

 Ptychaspis sp. 

 Cf. Saratogia wisconsensis 

 Ellipsoccphalus curtiis Whitfield 

 10. Thin-bedded and shaly, compact, hard, bluish-gray lime- 

 stone, with partings of dark argillaceous shale 17 5.1 



The thin-bluish-gray limestones' interbedded in the 

 shales were unfossiliferous as far as observed. 

 ip. Thick layers of gray limestone that break up into irregu- 

 lar layers on exposure to weathering. The limestone 

 varies in thickness from 16 to 24 inches (40.6 to 



60.9 cm.) in a distance of 30 feet (9.1 m.) 2 .6 



Fauna. — (2oi) : this is the most prolific in fragments of 

 fossils of the several gray limestone layers in the 

 section. It appears to carry the same fauna as (21s) 

 of in of section. 



BillhigscUa sp. 

 Ptychaspis sp. 

 Cf. Saratogia wisconsensis 

 EUipsocephalus curtus Whitfield 

 ig. Limestone and shale similar to 10 i .3 



