S. G. Williams — Gypsum Deposits in JVevi York. 213 



No. 3. Measures concealed, leveled with Locke-level, 20 feet. 



" 2. Thin-bedded blue limestone terminating below 



with a seam 2 feet thick, 4 " 



" 1. Drab limestone unevenly bedded with two or three 



thin blue seams, to Lake-level, 16 " 



The mean of four readings with the aneroid agrees well with 

 the total thickness here given. The beds No. 1 have yielded 

 fossils at three points, all at about the same level near the 

 middle of the series, viz : one head of Eurypterus remipes, and 

 tolerably abundant Leperditia alia, Nucleospira ventricosa and 

 Meristella bisulcala. Although the two species last named are 

 but imperfectly preserved, still the comparison of a considerable 

 number of specimens, among which are some fair casts of the 

 interior, leaves no good reason to doubt their specific identity ; 

 besides which, my own opinion is confirmed by that of the 

 experienced paleontologist, Mr. R. P. Whitfield, to whom a 

 number of the specimens were submitted. 



Besides the irregularities in the bedding of No. 1 mentioned 

 in the section, the strata in this region are occasionally affected 

 by local disturbances. The most common of these is a sudden 

 tilting of the beds at a low angle, continuing sometimes a 

 number of rods, which is caused apparently by a failure of sup- 

 port from below. One such disturbance occurs near the middle 

 of No. 1, causing the bfds to dip very perceptibly to the south- 

 east for a short distance. More considerable disturbances of 

 like character affect the Corniferous limestones of Union 

 Springs, about two miles south of the plaster quarries, two of 

 which have come under my notice. One of these, which was 

 mentioned and figured in the Report on the 3d District, and by 

 which the limestone is caused to pitch suddenly south at an 

 angle of 13°, has within the last two years, been more fully 

 developed by the opening of a large quarry immediately south 

 of the disturbed beds. In this quarry, which is capped by a 

 considerable thickness of Marcellus shales with a band of con- 

 cretionary limestone, is revealed a flat-topped anticlinal arch 

 with an E.-W. strike, the southern limit of which has not yet 

 been reached in quarrying, while the northward dipping side 

 with an angle of 20° is near the junction with the southward 

 dipping beds described by Yanuxem. In one of the most ex- 

 tensive plaster quarries also, there occurs a gentle anticlinal 

 with meridional strike, through which the present working floor 

 of this quarry and the one to the north of it, is made to dip 

 eastward at a small angle as far as the workings extend ; and 

 if this dip continues, it will increase by a number of feet the 

 space between Nos. 2 and 4 which was found by leveling to be 

 20 feet. The knowledge of these occasional irregularities de- 

 manded caution in assigning the gypseous series, with an average 



