798 NEW YORK STATE MUSEUM 



to Cadj sound. Tufa forms in exposed situations along tlie 

 deposit. 



Again in the town of Riga on the land of Mr Knowley, a de- 

 posit of marl of unknown depth covers 30 or 40' acres. It has 

 been penetrated 10 or 15 feet without finding bottom. The 

 upper 2 feet is very pure, but the lower part is sandy. 



The marl has been used for enriching soils, with very good 

 results at several points in the county. 



Montg^omery county^ 



Good exposures of the Calciferous occur near the l^ew York 

 Central railroad at Amsterdam and St Johnsville, Canajoharie 

 and Tribeshili 



According to Darton the Trenton limestone reaches its maxi- 

 mum thickness at Fort Plain, where it is 9 feet, but decreases to 

 T feet at St Johnsville. The limestone varies sometimes, being 

 massive at Tribeshili, and at other places shaly. In the Tribes- 

 hill quarries 12 to 15 feet of massive stone is exposed. Other 

 exposures are seen in the quarries north of Amsterdam. 



At D. C. Hewitt's quarry, 1 mile north of Amsterdam, the 

 Trenton rock has been used for lime. In the upper quarry the 

 stone is coarse grained, and the layers in upper portion of the 

 quarry are quite impure and shaly. The rock from this upper 

 quarry burns to a brown lime. In the lower quarry, which is 

 just below Hewitt's limekihi, the stone is much purer and more 

 massive than that of the upper quarry. The lower layers are 

 harder, are light gray and are said to make a whiter lime. Under 

 this comes a bed of lime rock which is practically non-slaking 

 and seems to have hydraulic properties. The lime made at this 



1 Darton, IST. H. Preliminary description of the faulted region of Herkimer, 

 Fulton, Montgomery and Saratoga counties {see 14tli an. rep't N. Y. state 

 geol. p. 33) 



■ Geology of Mohawk valley in Herkimer, Fulton, Montgomery and 



Saratoga counties, (sec 47th an. rep't N. Y. state mus. p. 603) 

 Yanuxem, Lardner. Geol. 3d dist. N". Y. 1842. 



