Note-Taking and the Use of Maps^ Etc. — Foerste. 235 
of a geologically varied country becomes often, therefore, a 
means of determining their superficial area in situ, and deter- 
mining their contact lines with others and especially when 
igneous rocks are present in districts otherwise unmanageable ; 
while the actually formed exposures serve as a check on this 
kind of work. N. and S. contact lines are not so readily 
determined in flat countries at least, the bowlders often devi- 
ating as much as thirty degrees from the course supposed to 
have been taken hj the moving agency ; still at times even this 
variation is not too great to admit of at least some results. In 
indicating the localities at which such observations are made 
on the map a dot is placed immediately after the number or 
some other sign is used to distinguish the same from localities 
where actual exposures have been found. 
The most convenient note book for general use is one in 
which all the leaves are cross-ruled by parallel lines 5 mm. 
apart dividing the pages into numerous squares. They should 
be stitched together along the end, and not on the side, and the 
writing should pass horizontally across the page, along its 
shortest diameter. The first three series of squares along the 
whole length of the book should be left free of all kinds of 
writing, being used solely for the indication of the locality, 
including the two letters designating the square and the num- 
ber designating the locality. In this way the pages may be 
readily scanned for some note desired, the letters indicating 
the locality, standing out clearly. Each page of the book 
should be numbered. At the end of the book the last three 
pages could be utilized by placing in an index of the notes. 
This is best done at the close of a season's work when the 
notes are being worked up, since the number of notes entered 
in different squares will be very unequal. The best series of 
indexing requires only two longitudinal series or columns of 
squares in the note book for each set of localities from the same 
square and consists in placing in the two squares at the head 
of two columns the letters indicating the particular square in- 
dexed in red ink. Then in black ink the localities of each 
square on the map are marked in the first column in the note 
book and the corresponding page on which the note itself is 
found is placed in the second column. One page will serve 
for several columns of this kind and three pages are usually 
sufficient for indexing one hundred pages of notes. Since this 
