216 S. G. Williams — Gypsum Deposits in New Torh. 



every place where it is laid open by workings ; the only excep- 

 tion that I could find being in the two northern quarries called 

 the Fitch quarries and which are but a few rods distant from 

 each other. Here the gypsum, which occurs in several thick 

 layers not well enough revealed to admit of definite measure- 

 ment but showing at least 12 feet, has above it about six feet 

 of black dirt resembling an impure leached gypsum which it 

 probably is, eight feet of very shaly drab limestone, and three 

 feet of somewhat firmer drab limestone containing Spin/era 

 Vanuxemi, a Lingula apparently undescribed, somewhat smaller 

 and more oval than L. spathata, fragmentary impressions of a 

 Khynchonella not sufficient for determination but having some 

 resemblance to R. mutabilis, and a slightly tapering fragment 

 2f inches long, nearly an inch wide at the widest end, and -| 

 inch wide at the narrowest, and marked lengthwise with 12 

 shallow furrows; this may possibly prove to be a plant allied 

 tC'Calamites. These fossils have been discovered since the first 

 part of this paper was written ; but their bearing on the ques- 

 tion of geological age will be obvious. The upper gypsum 

 bed shows little disposition to separate into distinct layers save 

 in the northern quarries, and is softer and somewhat less dense 

 than the seven-foot bed. It was thought also to be of better 

 quality until analysis showed it to be nowise superior. All 

 the members of the series show occasionally small spots and 

 thin scale-like laminae of sulphur, more especially on dirt 

 seams. The upper- bed, I am told, contains more of this sul- 

 phur than the lower, and the slate seam more than either. The 

 gypsum of both seams varies from a light to a somewhat dark 

 gray. 



The gypseous series here shows therefore no tendency to 

 form isolated masses, save where denudation may give it that 

 appearance, in which- case it is enveloped in drift clay. Two 

 proprietors of long experience however inform me that the 

 entire set of beds is occasionally cut across by what are called 

 " mud seams " from one to five feet wide, that the mud seams 

 are often of thin-laminated structure and sometimes contain a 

 little gypsum and selenite, and that the gypsum beds abut 

 against them regularly on both sides. The only example of 

 this kind of replacement that has come under my notice, was 

 in the edge of one of the quarries where, at the time of my 

 last visit, the lower gypsum bed and the "slate," the only 

 members there present, had suddenly given place below to 

 black thinly-laminated mud, and above to harder thin-bedded 

 ferruginous shale, the "mud seams" abutting against the gyp- 

 sum and "slate" in a reentrant fashion. The lamination of 

 the mud appeared to correspond to that of the gypsum against 

 which it abutted, and one block was hard gypsum at one end 



