we 
104 [Nov, 21, 
that the gypsum is not older than Tertiary times, and that it owes its 
origin (as in the Great Salt Lake of Utah) to the meeting of two systems 
of drainage witers, one from a region furnishing an abundance of lime 
water, and the other from a region furnishing an abundance of copperas 
water. 
This memoir is not only valuable for its new facts, but for its correction 
of mistakes made by me in my survey of the region in 1870,. A re-survey 
of any geological field by another, or by the same competent geologist, is 
sure to produce such results; and the ‘‘constants of science’’ can only 
be obtained by this process of reiteration. My mistake of identifying the 
fault at Saltville with the Walker mountain fault is a case in point. Prof, 
Stevenson shows their distinction. 
The total absence of the Catskill formation No. TX, and the nearly total 
absence of the Pocono formation No. X, two formations measuring 
together in Middle and Eastern Pennsylvania at least 8000 feet, is worthy 
of especial notice, as it goes far to confirm the apparent lack of IX and 
thinness of X at no great distance behind the Allegheny mountain in 
western Pennsylvania. As we know nothing of the south-eastern limit 
of these formations, and. merely see them at their last outcrop growing 
thicker in that direction, and also north-eastward, the idea of a closed basin, 
however large—perhaps extending to Scotland—may challenge respectful 
consideration, 
On motion, the Secretaries were authorized to publish a 
colored map of the district like that in Vol. XIX, page 219. 
2. The Limits of Stability of Nebulous Planets, by Prof. 
Daniel Kirkwood. 
3. On the Genealogy of the Vertebrata, and the Theory of 
Degradation as demonstrated by it, by Prof. E, D. Cope. 
The minutes of the last meeting of the Board of Officers and 
Members in Council were read, and on motion the recommen- 
dations therein contained were approved, and adopted. 
1. Resolwed, That the Proceedings be hereafter published quarterly,’ or 
oftener, at the discretion of the secretaries. 
2. Resolved, That all members not paying an annual cotta tivation be 
charged one dollar annually for the printed Proceedings, 
It was explained that the Post-Office laws of the United States require 
not only a quarterly issue, but a bona fide subscription list, for placing any 
printed matter under the head of third-class matter. 
The Secretaries will not only make this notification and explanation,) 
but will send a circular letter to such members of the Society soliciting 
their assent, 
3. Resolwed, That the Indian Picture Rock be obtained at a total cost 
not exceeding $50 for purchase, preparation and transportation. 
