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GEOLOGY OF THE THIRD DISTRICT. 
CHAPTER XII. 
Of the Rocks collected for the State and for the Colleges. 
The collection of rocks which was made for the State Cabinet, is nearly arranged, and upon 
a plan which affords an opportunity of becoming readily acquainted with the whole of the 
rocks of the State, according to their mineral and especially their fossil character, and in the 
exact order of superposition. The plan adopted was to appropriate the whole of the upper 
part of the building to the Geological department, making a twofold division in the department, 
reserving the whole of the lower floor for a systematic arrangement according to kind and 
order of superposition; keeping the gallery which surrounds the room, exclusively for a geo¬ 
graphical collection, or according to the counties ; so that the local, the economic interest, as 
well as original products, and those which were the result of decomposition or alteration of 
original products, shoidd be placed together, being the only way to prevent that confusion 
which is produced in the mind when all are in juxtaposition. The first floor is reserved for 
the great masses of original products, in their order of succession, the object of which is to 
make known the history of the earth by the products which have followed each other in regu¬ 
lar sequence. The arrangements on the first are nearly completed, wanting a few more tables. 
Those of the gallery are not commenced, excepting temporarily by Mr. Mather; but enough 
there will be done, to show the utility of that reservation, or the collection which will there be 
exhibited. 
The plan of arrangement upon the lower floor, consists in having a Table with a glass cover 
for each rock, group or geological element, with the name in large printed letters on the front 
side of the table; having nothing within each table but what was known with certainty to 
belong to it as an original product, each product having a place, and each product in its place. 
The tables, as they represent a rock or group, are arranged around the room, at some distance 
from the walls, in the form of a parallelogram, and in the order of their succession, com¬ 
mencing with the primary, placed near the door at the left hand, the order being from left to 
right. Thus, in a few hours the examiner is carried from a table which contains the rocks 
of the Primary system, to the one which holds those of the Catskill group ; at the right of 
which is another table, containing a suite of the Coal rocks of Pennsylvania, placed merely 
for those unacquainted with them, that they might have an opportunity of at once observing 
the difference between them and all those rocks below, or to the left hand, which form the 
