Wadsworth.] 
272 
[October 19, 
CONCLUSION. 
In questions relating to this Fortieth Parallel collection regard 
has to be paid to the conditions under which it has been preserved 
and the difficulties under which one examining it must labor. 
The specimens as collected in the field were numbered, but in 
the cabinet different numbers were again assigned them, and these 
latter in general are the numbers on the microscopic sections. 
Again, when Zirkel’s report was published, the numbers given 
therein were entirely distinct and intended simply to enumerate 
(with some omissions) the rocks in the order in which they 
were described. The specimens, unnumbered , lay loose in drawers, 
placed on the labels which bear the first two sets of numbers. 
The specimens, not even being in paper trays, roll off their 
labels and about the drawers when they are opened. In this 
condition, without any numbers upon the specimens, they have 
been twice moved, I am informed, to different buildings and 
into different drawers, as well as part having been twice sent 
across the Atlantic. Also they were handled at wall by all visi- 
tors who were admitted to the room. 
Such was the condition of things at the time of my examina- 
tion. In all cases of criticism the writer gave Professor Zirkel 
the benefit of the doubt that must arise in a collection treated in 
that manner, and required that the specimens and slides should 
correspond with the descriptions given in Volumes VI and II 
sufficiently to identify the rocks as the ones described. The 
slides, of course, bore the same numbers as the numbers in Zirkel’s 
manuscript, and therefore comparatively only a few cases of 
doubt could arise regarding them. 
Again, the names of the localities have in many cases been 
given differently in the published reports, and upon the labels. 
No set of coordinate numbers of reference have been employed, 
whereby the history of the rocks can be traced through the 
different reports, while the numbers of the pages referred to have 
rarely been given. The tracing of the descriptions of the speci- 
mens through the different reports is a work that involves much 
time and labor, which not unfrequently is fruitless. 
