264 



NEW YORK STATE MUSEUM 



The fprmation in the two localities is 40 to 60 feet thick and con- 

 sists of impure magnesian Hmestones in rather massive beds of fine 

 texture. The rock has not been employed to any great extent for 

 other purposes. The Manlius limestone is worked for natural 

 cement in Onondaga county, where there are two beds of water- 

 lime measuring about 4 feet thick, in character an argillaceous 

 dolomite, separated by a comparatively pure, blue calcareous limestone 

 of similar thickness. The blue limestone associated with the cement 

 layers has been extensively employed as cut stone in Syracuse and 

 vicinity; it is usually worked in connection with the overlying Onon- 

 daga limestone. The quarry localities are mentioned under that 

 formation. In eastern New York the Manlius is exposed along the 

 west side of the Hudson river in Greene and Albany counties, also 

 in Becraft mountain, Columbia county, and in Schoharie county, 

 where it has been a source of building stone, crushed stone^and of 

 lime. It is here a fairly pure calcium limestone. 



Analyses of Silurian limestones 



SiOz . . . 

 AljOs. . 

 Fe203. . . 

 MgO. . 

 MgCOa. 

 CaO.... 

 CaCOs . 

 CO2.... 



.90 

 .68 



4-95 



92.99 



10.40 

 5.20 



30.25 

 52-54 



3 40 

 .60 



I 



7 



J I 



30 



I 



75 



17 



45 



32 



21 



46 



79 



7 

 2 



09 

 57 

 96 



33 



42 



56 



19 



20 



7 



95 



8 



05 



30 



5 



45 



24 



• 29 



•43 

 .46 



43-3 

 56.01 



SiOa. . . . 

 AI2O3. . 

 FeaOj... 

 MgO. .. 

 MgCOs. 

 CaO.... 

 CaCOa. 

 COo.... 



30- 



51 



4.02 

 1.48 

 1.07 



35 09 



"57-87 



1.6 



■ 7 



I . II 



97- 



5-35 

 f .56 



\ .61 



' "i8!86 

 ""85'.4i 



10 



97 



4 



46 



I 



54 



16 



9 



27 



51 



37 



94 



