22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



OZARKIAN 



MoNS Formation : p^^, ^^^^^^ 



1. The highest beds exposed are two bands of hard gray intra- 



formational conglomerate limestone some 6 feet 

 (1.8 m.) in thickness separated by 3 feet (.9 m.) of 

 gray silicious shale. (Dip 80° N. 65° east. Strike N. 

 25° west.) 



Below, there are single layers and bands of hard, silicious 

 steel gray limestone with stringers and very thin layers 

 of gray chert and layers of irregular intraformational 

 limestone conglomerate made up of small lumps of 

 what appears to have originally been calcareous mud, 

 also thin irregular bits of gray limestone with angular 

 or rounded edges, all of which are interbedded with gray 

 silicious shale in which occur thin layers of limestone 

 .25 inch to 2 inches (.6 to 5. cm.) thick. Thickness 

 of I 705 214.9 



Fauna. — Many bits of comminuted tests of trilobites and 

 fragments of shells occur at several horizons but the 

 only recognizable forms found were near the top and 

 consist of a single ventral valve of Syntrophia cf. isis 

 Walcott, a whorl of a small depressed gasteropod, and 

 a fragment of the test of a trilobite. 



2. Hard, steel gray, fine grained, compact magnesian lime- 



stone in layers 12 to 30 inches (30.4 to 76.2 cm.) thick, 

 with much included light gray weathering chert in thin 

 layers .5 to 2 inches (1.2 to 5. cm.) thick, and numerous 

 irregular cherty nodules 83 25.3 



A silicious or finely arenaceous shale forms parting between 

 some of the layers. 



Fauna. — No fossils observed. 



3. Alternating bands of calcareous and silicious shale with 



layers of gray limestone of varying thickness and char- 

 acter ; the limestone may be dove colored, compact with 

 conchoidal fracture, hard dark gray with silicious shale 

 in thin irregular laminations, irregular nodules of small 

 size scattered through or mainly composing it, and a few 

 thin layers of soft, gray, more or less finely crystalline 

 limestone crowded with broken and rolled fragments 

 of the tests of trilobites 648 197.5 



In the upper 100 feet (30.4 m.) there are a few thin layers 

 of light gray weathering chert running along irregularly 

 with the bedding of the limestone and shale. 



The strike of the beds in the upper two or three hundred 

 feet (60.9 or 91.4 m.) is N. 15° west, and dip 70° N. 75° 

 east. 



Fauna. — In a layer of hard, dove colored to gray limestone 

 30 inches (76.2 cm.) thick that occurs 113 feet (34.4 m.) 



