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GEOLOGY OF THE THIRD DISTRICT. 
No. 1. A single hopper-shaped form from Bulls’ quarry, town of Lenox, Madison county, and resembling those which are formed 
upon the surface of the solar salt pans. 
No. 2. Exhibits three of the same forms, being one-half of a cube, their apex pointing to a common centre ; from Kelly’s quarry 
in the same town. 
No. 3. Shows a congeries of hoppers disposed in a line, the specimen from Bulls’ quarry in Lenox. The line which crosses 
the range of crystals or forms, shows they were formed when the mass was in a measure desiccated or dried. 
Hopper-shaped Cavities. The most interesting of all the products of the group are the 
hopper-shaped forms and cavities, the wood-cut showing three different appearances of them. 
These forms and cavities are of great importance, for they were produced by common salt, 
no other common soluble mineral presenting similar ones. They show that salt existed in 
the third deposit, and the position which they hold in the deposit should regulate all future 
borings that may be made for rock salt. These cavities are in shape like a mill hopper, 
whence their name. When salt is observed to crystallize, a cube first makes its appearance 
upon the surface of the brine ; this sinks gradually, as a series of similar cubes form around 
its outer border, being attached to its upper surface near its edge. When these are com¬ 
pleted, the whole sinking as additional particles are added, another row of cubes are formed 
upon the first range ; and thus for many repetitions, until the density of the mass formed becomes 
greater than the liquid, when it falls to the bottom. When examined, being turned upside 
down, it shows a pyramid of regular steps, terminated by a cube ; and when its position is 
reversed, a form like the hopper of a mill: its perfection depending, as in all other cases, 
upon the absence of interfering or disturbing causes. No. 1 of the wood-cut shows a single 
pyramid or hopper, but the cubic arrangement is wholly indistinct. 
In all the localities where two ranges of plaster beds are seen, the hoppers occur between 
them, and between the two masses of vermicular rock : they are from one to three and more 
