276 bulletin: museum of comparative zoology. 



AssERiEN. (Zones 16 to 13 are well shown in the quarries and along 

 the railroad about two miles south of the cement plant at Asserien. 

 Zones 13 to 1 are well exposed at and below the large quarry at the 

 edge of the cliff about a mile west of the plant. Measured by Dr. 

 Twenhofel and the ^VTiter). 



16. Fine-grained magnesian limestone in layers one to three 



inches thick. Very few fossils. 6 ft. — 76 ft. 1 in. 



15. Thick-bedded, fine-grained compact magnesian lime- 

 stone with an abundance of Orthoceratites in the lower 

 three feet. Some la^^ers are porous and show open moulds 

 of fossils. 8 ft. = 70 ft. 1 in. 



Zones 15 and 16 belong to the Reval formation. 



14. Thick- and thin-bedded gray limestone without much 

 shale. Echinosphaerites especially abundant in the 

 lower part. 7 ft. 6 in. = 62 ft. 1 in. 



13. Light gray, rather thick-bedded limestone without 

 shale, but becoming soft and shaly on weathering. This 

 zone contains more or less "linsen" throughout, but 

 they are especially abundant in the lower three feet. 



8 ft. = 54 ft. 7 in. 

 Zones 13 and 14 make up the Dubo^N-iki formation. 



12. Thick- and thin-bedded gray limestone which becomes 

 soft and shaly on weathering. Many Vaginoceras 

 present. 14 ft.' 8 in. = 46 ft. 7 in. 



11. Lower "Linsenschicht." 9 in. = 31 ft. 11 in. 



Zones 11 and 12 represent the Kunda formation. 



10. Thick-bedded gray limestone. 3 ft. 6 in. = 31 ft. 2 in. 



9. Thin-bedded limestone and shale. 6 in.- = 27 ft. 8 in. 



8. Thick-bedded, hard, reddish limestone with glauconite. 



3 ft. 



7. Clay and limestone. * 



6. Green clay and sandstone. 6 ft. 



Zones 6 to 10 form the Walchow formation. 



5. Thin-bedded, soft, yellowish clay-shale. 



4. Red and yellow limonite. 



3. Thin-bedded black shale with thin layers of sandstone 



in the lower half. 7 ft. = 12 ft. 6 in. 



2. Light yellow and red cross-bedded sandstone, with 

 lenses of thin, black shale in la^|prs one fourth to one inch 

 in thickness and with black deposits on the bedding 

 planes. 3 ft. 3 in. = 5 ft. 6 in. 



