68 J. A. UDDEN 



the creek, and they are also seen in a small tributary which runs 

 into the creek from the east. Combining all the exposures at 

 this point the following succession of separate layers is evident. 



Number Feet 



1 1 . Dark gray bituminous shale with one or two thin green bands about 

 four feet below the highest exposure. Occasionally small flat 

 concretions of pyrites are seen. Next the green layer the 

 shale is dark filled with a maze of fine green filamentous lines. 

 Drift overlies - ... 8 



10. Dark shale containing lingulas, Spathiocaris emersoni, Rhynchodus, 

 and a fossil resembling Solenocaris strigata. This number is 

 continuous with No. 1 1 - - - - - - i Y? 



g. Greenish clay with flat concretions of iron pyrites frequently hav- 

 ing white stony lamellar extensions from the margin - - 3 

 8 . Dark shale - - ....... y 3 



7. Greenish stony shale with a conchoidal concretionary fracture, - % 

 6. Hard light grayish-green shale with white flattened cylindrical fucoid 



concretions of a concentric structure in horizontal positions - %-]/?. 

 5. Greenish argillaceous or arenaceous fine-grained dolomite in ledges 

 from 4 to 10 inches in thickness, with occasional lingulas and 

 a fragment of a cast of a gasteropod near the base, frequently 

 exhibiting small cylindrical concretionary impregnations of a 

 deeper green, and occasionally impressions of plant-like fibrous 

 structure covered with a thin layer of bituminous material - 3 

 4. Greenish shale - - - - - - - - - - 1 X 



3. A stony seam filled with finely granular pyrites and occasionally 

 showing larger lumps of the same mineral in one instance asso- 

 ciated with plant-like fibrous impressions, frequently containing 

 rounded worn fragments of fish teeth - tV-X 



2. Green hard shale ......... y 



1 . Greenish stony layer with frequent, mostly rounded, fragments of 



Ptychtodits calceolus -------- j^ 



Under the lowermost layer containing fish teeth the uneven 

 surface of the upper ledges of the Cedar Valley limestone is 

 seen, and at least eight feet of this rock is exposed. In some 

 of the shallow depressions in its upper surface a seam of black 

 bituminous material is found. At one point this forms a layer 

 two inches in thickness. Near the south end of the exposure 

 farthest down the creek the upper beds come down over the 



