Handbook of Paleontology 345 



been found in these beds at Howe's Cave in the Cobles- 

 kill area, having passed up from the underlying Cobles- 

 kill limestone. 



The Manlius limestone (Clarke and Schuchert '99) 

 was named from the exposure at Manlius, N. Y., and 

 includes near the top in Onondaga county two thin beds 

 of waterlime which are used for cement. This forma- 

 tion has been known as the "Tentaculite limestone" (Geb- 

 hard, Mather and others) from the abundant occurrence 

 of Tentaculites gyracanthus, and the "Waterlime group 

 of Manlius" (Vanuxem '39). It extends under the 

 Coeymans limestone (Lower Devonian) as far west as 

 Onondaga county, and west of this is overlain by the 

 Oriskany or Onondaga to the limit of its extent in 

 Seneca county. The only occurrence of the Manlius on 

 the east side of the Hudson valley is an outlying area at 

 Becraft mountain where it is being quarried for cement. 

 It is also quarried for road metal in a number of locali- 

 ties. The Manlius, typically, is a thin-bedded, dark blue 

 limestone of fairly pure composition. The layers are one 

 to three inches or more thick, and are especially thin 

 in the lower part with alternating light and dark beds 

 ("ribbon-limestone"). The slabs of this limestone break 

 with a ringing sound, and the rock when weathered has 

 a characteristic light color. Because of the hardness of 

 the rock it tends to form a distinct vertical cliff by itself 

 or together with the Coeymans limestone above (figures 

 51, 52). The Manlius beds have a maximum thickness 

 of 150 feet, more or less, in the central part of the State, 

 but in the Helderberg and Schoharie areas there is a 

 thickness of about 50 or 55 feet. In the Helderberg area 



