()2 Tfii' AiHei'ictin (jrolof/ixt. J.muiiry, WW?- 
I. Tlie unit of ari'ii sliall hi' a geoffrapliic <>iu' and shall lie a rracrioii 
of siiuare degree of latitude and longitude 
'2. The size shall be uniform and rln' sliprt . including I In- margin, shall 
he 17I4 X 2lJ'4 inehes. 
■S. The map shall be inserted witiiout folding in a report of folio form 
of whieh the page of text shall t)e of the same size as the map. 
My chief objections to the j)lan j)rop()sed by you are: that it restricts 
the use of a large scale and that it ])revents tlie adoption of anything 
like a uniform scale. Further, a county is not a tixed unit. l)ut is 
liable to be changed cionstantly by subdivision. 
Counties are of extremely variable areas. Within the I'nited States 
they range from 25 .s(]uare miles to 12,000 s(|uare miles in extent ; while 
counties of 200 s(|uare miles and 1.000 sijiuire miles in the same 
state are common. In Minnesota the smallest county is 162 stpiare 
miles in extent, while the largest county contains 5,8(10 scpuire miles. 
In ^fissouri counties range similarly from 270 to 1.145 .scjuare miles in 
area. The limits of a quarto page for mai)s of these areas would allow 
the scale, in some cases, to be as much as 2 inches to one mile ; whereas, 
in another case, it would have to be as little as 1 inch to 1 1 miles. For 
counties in ^lissouri the largest scale ])ermissible would he 1 inch to 
1/u luiles and the smallest scale would he I inch to ."}'.. miles. In 
]^[iimesota, similarly, small and large counries would have to he repre- 
sented on scales varying between 1 inch — ly-'„ miles and one inch = 
7*0 miles. 
It would be sui)ertluons to argue hefoi'e you tin- nccessily of using 
a larger scale than the size you fix will permit, for the representa- 
tion of all the valual)le detail which we try to include in onv modern 
geological maps. 1 take it for granted that you will recognize this 
without further demonstration, and it seems to me that this is an in- 
superable objection to the limitations of a (juarto page. (iranting 
this conclusion, the alternatives which suggest themselves for obviat- 
ing the ditiiculty are as follows: 
A. To retain the county as the unit of area and to make the sheet of 
uniform size, but to enlarge the sheet to such a size that the larg- 
est counties can be represented in all the detail necessary. 
B. To retain the county as the unit of area hut to at)andon uin'form- 
ity in the size of the sheets. 
C. To abandon the county as the unit of area hut (o retain uniforn)ity 
in the size of sheet. 
Adojiting the first alternative (A ), the county J.OOO sijuare miles in 
area, mapped on a scale of one inch to the mile, would require a sheet 
at least 32 inches stjuare ; a county 5,000 square miles in area, mapped 
on the same scale, would require a sheet 72 inches square. .\. plan of 
publication necessitating such large sheets as this for small as 
well as large counties, is plainly out of the question. 
According to the second alternative (B), a county of I60 square 
miles, mapped on a scale of one mile to an inch, could he plotted on a 
