820 NEW YOEK STATE MUSEUM 



The ledges are most prominent at tlie track level about I mile 



south of Lansing. The stone is fine grained, moderately hard, 



and shows occasional impure layers, but comparatively few 



chert nodules, the impurities being mostly iron and clay. It is 



a massive rock, with layers 2 to 3 feet thick, the total thickness 



being about 20 feet, and is favorably situated for either rail or 



water shipment. 



An analysis made of samples taken by the writer from the ledge 



south of Lansing showed: 



Silica 5.7 



Alumina ) ^ 



Ferric oxid j 



Lime carbonate 88.5 



Magnesium carbonate . 1.4 



Insoluble 8.8 



Ulster county^ 



The limestone formations occurring in Ulster county together 

 with their thickness are as follows: 



Feet 



Onondaga , 60 Cherty 



Upper shaly limestone 30-125 Impure 



Becraft limestone 20-30 Fairly pure 



Lower shaly limestone 60 Impure 



Pentamerus limestone 30-60 Dark massive 



Tentaculite limestone 20-40 Thin bedded 



Cement series '....., 20-50' Cement and waterlime 



ISTiagara limestone 0^45 



Wappinger limestone . 200 Silicious 



1 Darton. Geology of Ulster county, (see ISth an. rep't N. Y. state geol. 

 p. 207). 



Dale, T. N. The fault at Eondout. {see Am. jour. sci. 1879. 18: 293) 



Davis, W. M. The little mountain east of the Catskill. {see Appalachia, 

 3: 20) 



. Non-conformity at Rondout N, Y. {see Am. jour. sci. 1883. 



26: 389) 



. Becraft mountain, {see Am. jour. sci. 1883. 26: 381) 



. The folded Helderberg limestones. (seeBul. Mus. comp. zool. Har- 

 vard col. 7: 311) 



Lindsley. Geology of the cement quarries, {see Poughkeepsie soc. nat. sci. 

 11: 44) 



Nason, F. L. Economic geology of Ulster county, {see 13th an. rep't N. Y. 

 state geol.) 



Mather, W. W. Geol. 1st dist. N. Y. 1843. 



