﻿57 Union Springs 



certainty. We have never had the pleasure of seeing the quar- 

 ries drained so as to measure the depth to which the deposit ex- 

 tends. Williams has assigned it an average thickness of 

 25 ft. But, inasmuch as a workman at the Plaster Mills says 

 the quarry has a face of 50 ft. when drained, and since the dip is 

 considerable in a southerly direction at Cross Roads, and east at a 

 point a few hundred feet west of Thompson's old quarry where 

 the Eurypterus rock disappears beneath the gypsum horizon, it is 

 quite evident that in places a thickness of 40 ft. ma)' 

 well be assigned to these deposits. 



We should observe in passing that Clarke and L,uther have 

 unfortunately considered the outcrop of the gypsum deposits in 

 this region as due to a local anticline, bringing them up to the 

 surface, while the Eurypterus limestone and the few feet of thin 

 gray shaly Salina limestone just below the Cobleskill are con- 

 sidered as one and the same deposit, flanking the anticline north 

 west, and south-east. The fallacy of this interpretation is at 

 once evident when one looks carefully into the kind of rock, 

 thickness of beds, and fossil remains of each of the two limestone 

 horizons ; also when one sees, at Cross Roads for example, the 

 Cobleskill limestone on a hill but perhaps 300 feet south of a 

 southward dipping bed of Eurypterus limestone in the bank of 

 the stream opposite the old water mill. 



In Hartnagel's article already referred to (p. n 36) he remarks 

 regarding the condition of affairs at Thompson's quarry : "This 

 outcrop in the cut however, is on the other limb of the anticline, 

 with a dip strongly towards the northwest." Various pieces of 

 rock have slid down from the top of the cut and rest at various 

 angles, but the dip at this locality is moderate and in a south- 

 easterly direction. The "anticline" has no real existence. The 

 stratigraphy of the region is much more simple than this anticlinal 

 theory would lead one to suppose. Williams clearty stated the 

 true sequence of beds here as early as 1885. (See Amer. Jour. 

 Sci., 3d ser., vol. 30, p. 213-214.) We are well aware of the lo- 

 cal anticlines, synclines and domes in this region, caused mainly, 

 we judge, by the dissolving out of lime, gypsum, and salt layers 

 in certain localities and allowing the beds above to sink down in 

 a very irragular manner. But there is no evidence to show that 

 the gypsum beds about Union Springs are below the limestone so 

 well exposed at Cayuga Junction and containing in places so 



