176 THE FORMATION 
photographs often taken from a boat, but otherwise the usual methods apply, 
at any rate for bogs and shallow bodies of water. In lakes or streams the 
tapes might be attached to buoys or floats. The determination of factors is 
made as usual. Permanent quadrats are feasible in many cases at least, and 
denuded quadrats are not altogether impossible. 
TRANSECTS 
217. The transect is essentially a cross section through the vegetation of a 
station, a formation, or a series of formations. It is designed primarily to 
show the order of arrangement of species in zones and societies, but it also 
serves as a record of the heterogeneity of any area. In the form of the layer 
transect, it furnishes a graphic method of representing the spatial relations 
of the species in layered formations, e. g., forests, ponds, and lakes. It is 
merely a logical exterision of the idea underlying the quadrat, and the tran- 
sect is, indeed, little more than an elongated quadrat. An important differ- 
ence, however, lies in the fact that the former normally traverses areas more 
or less unlike, while the latter is always located in a homogeneous one. Fur- 
thermore, the transect is plotted with especial reference to the topography. 
With respect to dimension, transects are classified as line, layer, and belt 
transects, and the latter may also be permanent or denuded. 
The Line Transect 
218. Description and method. A simple transect is sometimes made by 
establishing the points between which it is to be run, and then recording the 
plants pace by pace along this line. This is satisfactory where the striking 
changes in structure are desired. A more accurate method is ordinarily used, 
since it gives detailed results, and at the same time brings out the more gen- 
eral features. For this, use is made of a tape of proper length which is 
divided into decimeters. Tapes of 10, 50, and 100 meters are used, and if 
they are furnished with eyelets, transects of intermediate lengths may be.run 
with them. When longer transects are desired, as in the case of forest for- 
mations, tapes of 500 or 1,000 meters should be used with eyelets a meter 
apart. The transect is located in the area to be studied by running the tape 
from one landmark to another, fastening it here and there by means of quad- 
rat stakes. Previous to this, the shortest distance between landmarks is as- 
certained when the transect runs through a depression or upon a level surface. 
In the case of an elevation, the height is ascertained by a barometer, the 
length and angle of the two slopes obtained, and the length of the base line 
determined from these data. The field record of the arrangement of the 
