NO. I FORMATIONS OF BEAVERFOOT-BRISCO-STANFORD RANGE 2"] 



of the Mons formation, 3,175 feet (967.7 m.), having a combined thickness of 

 4,940 feet (1,505.7 m.), in the Sinclair section, are not present. There does not 

 appear to be any evidence of the faulting out of these formations or of their 

 removal by erosion prior to the deposition of the Silurian. It appears to be 

 an example of non-deposition and the overlap of the Silurian on the lower 

 Mons in this area. 



On the southwest angle of Sabine ]\Iountain the hard upper shales of la of 

 the Mons form a dark colored cliff above the softer, light gray shales beneath. 

 In the face of the cliffs on the south face of the mountain there appears to be 

 an unconformity between the Mons and the superjacent Silurian, but this may 

 be only a local upturning of the Mons shale against the massive-bedded Silu- 

 rian limestone ; usually the shales and limestone appear to be conformable. 



OZARKIAN 



Mons Formation : r- . ^^ . 



Feet Meters 

 la. Dark, compact, argillaceous shales with interbedded irregu- 

 lar layers of hard, compact, gray limestone in stringers 

 and a few layers 3 inches (7.6 cm.) to 12 inches 



(30.4 cm.) thick 156 47.6 



Fauna (near top locality I7t.) 



BillingscUa origen Walcott 

 Hncnella juha Walcott 

 Fragments of trilobites 



lb. Compact, hard, gray limestone 6 1.8 



ic. Somewhat softer, dark gray shale with occasional inter- 

 bedded, more or less irregular layers of dark gray 



limestone 54 16.5 



id. Massive-bedded thin layers hard gray limestone with part- 

 ing of gray shale 48 14.6 



Fauna (locality I7r.) 



Oboltis sp., fragment 

 Eoorthis iophon Walcott 

 Eoorthis cf. wichitaensis Walcott 

 Agnostus cf. josepha Hall 

 Ptychaspis 2 sp. 

 Conaspis cf. anatina Hall 

 Cf. Saratogia zvisconsinensis Owen 

 le. Compact, hard, gray, buff weathering limestone in layers 



6 to 14 inches (15.2 to 35.5 cm.) thick 4 1.2 



Strike N. 20° W., Dip 40° N. 70° E. 

 if. Gray shale with layers of buff weathering gray limestone 

 .25 inch (.6 cm.) to 6 inches (15.2 cm.) thick that at 

 17 feet (5.2 m.) down form a solid band of layers, the 

 shale having disappeared 29 8.8 



Total 297 90.5 



Fauna (locality 17s.) 



Obolus sp. undt. 



Agnostus cf. josepha Hall 



Ptychaspis sp. 



Cf. Saratogia zvisconsinensis (Owen) 



