NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 347 



Feet Meters 



These limestones form cliffs on the upper edge 

 of the mountain overlooking Glacier Lake Canyon 

 valley. 



A few small fragments of trilobites were observed. * 



2a. Purple-colored siliceous shale i8 5.4 



2b. Thick layers of a compact, finely laminated, dove-colored 



limestone 72> 22.2 



2C. Gray and dove-colored, massive-bedded limestone that 



contains considerable arenaceous matter 155 47.2 



2d. Purple, siliceous shale that passes by gradual intercala- 

 tion of hard gray, finely grained limestone below. ... 90 27.4 

 Fauna.— {64^) : At 62 feet (18.9 m.) above the base a band 

 of greenish gray, arenaceous shale contains a few 

 specimens of a small Obolus and Lingulella issc (Wal- 

 cott), and fragments of a small trilobite. 



2e. Limestone similar in character to 26 136 41.4 



Three beds of ferruginous, arenaceous limestone 

 I to 2 feet (.3 to .6 m.) thick are inter bedded in the 

 upper part of the limestone. 



2/. Greenish siliceous shale 9- 2.7 



2(7. Limestone similar to 2I1 52 15.8 



2h. Greenish siliceous shale 11 3-3 



2i. Limestone similar to 2b 51 i5-5 



Minute fragments of trilobites and Obolus occur 

 in several of the layers of limestone. 

 2/. Greenish siliceous shale marked by numerous sun-dried 



mud cracks 8 2.4 



2k. Limestone similar to 2b 13 3-9 



2I. Purple siliceous shale, with some interbedded greenish 



shale and calcareous shale 17 5-i 



2ni. Thick layers of dove-colored, compact, finely lami- 

 nated limestone 12 3.6 



This limestone and similar bands above appear to 

 have been formed from a calcareous slime or mud 

 spread in very thin layers rather slowly and evenly. 

 It suggests a glacial mud precipitated from the waters 

 derived from a glacial stream. 

 2n. Greenish-drab and gray siliceous and partly argillaceous 

 shales, with interbedded, hard, compact, buff-weath- 

 ering, thin layers of gray limestone near the base 221 67.3 



At about 25 feet (7.6 m.) from the base a massive 

 bed of purple-colored, hard siliceous and argillaceous 

 shale begins and continues on up nearly 200 feet 

 (60.9 m.). 



Total of 2 866 263.8 



Total of Arctomys formation 1,386 422.4 



