LIME AND CEMENT INDUSTEIES 757 



In tlie Moliawk valley only tlie Birdseye and Trenton members 

 are present. The Birdseye member is in greater part a fine 

 grained, dove colored stone, and Aveatliers light gray, and the 

 beds are generally moderately heavy. The exposures are com- 

 mon in the llohawk valley and have been quarried at a number 

 of localities. Underlying this rock is the Calciferous sandstone. 



According to Barton-"- the formation reaches its maximum thick- 

 ness at Fort Blain, where it is about 9 feet thick. It then de- 

 creases westward to 7 feet near St Johnsville. It is 5 feet on 

 East Canada creek, 4 feet aroimd Little Falls and to the south- 

 eastward, and 5 to 6 feet on West Canada creek about Middleville^ 

 JSTewport and Cold creek. 



At Ingham Mills the rock is well exposed in Butler's lime 

 quarry. At this point nearly 15 feet of a good grade of stone is 

 exposed. At Canajoharie the Trenton member of the group ap- 

 pears. Excellent exposures occur near Amsterdam and at Glens 

 Falls. At this latter locality the quarries are of special import- 

 ance. The Trenton limestone member is found extending east- 

 ward from Oneida county to Glens Falls. At times the rock is 

 massive as at Tribeshill, at others it is somewhat shaly. The 

 thickness in the quarries at Tribeshill is 12 to 14 feet of massive 

 stone. Other exposures also occur in the quarries about Am- 

 sterdam and again in quarries 2 miles northwest of Iloffmans 

 ferry, where about 20 feet of a soft, highly fossiliferous lime- 

 stone is exposed. 



A belt of Trenton occurs west of Saratoga and is well exposed 

 at Howland's mill 3 miles due west — southwest from Saratoga 

 Springs. The section here shows 20 feet of limestone. 



At Glens Falls the Trenton limestone is well exposed on both 

 banks of the Hudson, and is of much importance, being used for 

 building stone lime and Portland cement. 



Barton gives the following section of it. 



Feet 



Thin bedded black limestones in beds 3 to 8 in 10 



Black marble 10 to 14 in. beds 



* 15th an. rep't N. Y, state geol. p. 516. 



