RAYMOND: CORRELATION OF THE ORDOVICIAN STRATA. 273 



Bii|3. Thin-bedded limestone with red and yellow spots. 



Very little glauconite. 1.8 m. = 3.45 m. 



B,ja. Thick-bedded, red, yellow, violet, and gray-green 



limestone. 1.65 to 1.80 m. = 1.65 m. 



Section on the Walchow. (Measured by the writer). 



The highest beds are exposed in the quarries at Dubowiki. Zones 

 11 to 9 were measured near the steamboat landing at St. Michael 

 Archangel, and the remainder of the section on the eastern bank of 

 the Walchow opposite Iswos. 



11. Light gray to yellowish magnesian limestone in beds 

 one inch to one foot in thickness. Some layers are fine 

 grained and dense, while others are porous, the fossils 

 occurring as hollow moulds. Christiania oblong a com- 

 mon and characteristic. Reval formation. 25 ft. = 112 ft.± 



10. Soft gray limestone which breaks down readily to a 

 sticky calcareous mud. Entire trilobites and other 

 perfect fossils common. Echinosphaerites aurantium 

 abundant. 

 Dubowiki formation. Base not exposed. 14 ft. = 87 ft.=t 



9. Concealed to river level. 23 ft. = 73 ft.± 



(According to the thickness given by Lamansky the 

 greater part of the concealed interval here would be filled 

 by the "Orthoceras" limestone (Kunda formation)). 



8. Red and green limestone enclosing the " Lower Linsen- 



schicht." • 3 ft. = 50 ft. 



7. Thin-bedded limestone and shale, with 3 feet of rather 

 solid limestone at the top. B^s (B,jj« of Lamansky). 



9 ft. = 47 ft. 



6. Thick-bedded gray limestone with shaly partings. 



(B„^) 10, ft. 6 in. = 38 ft. 



5. Thin-bedded, shaly limestone. (B,i^). 5 ft. 6 in. = 27 ft. 6 in. 

 Heavy-bedded red limestone with abundant glauconite 

 and echinoderm fragments. (B,i„). 6 ft. = 22 ft. 



Sandy shale. 1 ft. = 16 ft. 



Zones 3-7, and the lower part of zone 8, below the 

 Linsenschicht, belong to the Walchow formation. 

 Concealed. 3 ft. = 15 ft. 



White and gray sandstone to the river's edge. Zones 1 

 and 2 belong to the Packerort formation. 12 ft. = 12 ft. 



c 



*& 



