Watchung
How Topography Affects Human Activity
You are going to study the relationship between people and the
surface of the land by looking at part of the Watchung Mountain area
of north-central New Jersey. First, you will examine how people have
adjusted their activities to the environment of this area. By knowing a
few simple characteristics of the landforms, rocks and soils of the
Watchung Mountain area, you will be able to make some hypotheses
(educated guesses) about where agriculture, settlement,
transportation routes, and industry are most likely to be found. After
you have made these predictions and then compared them with actual
development in the area, you will look at how our changing technical
abilities and desires have led people to respond differently to some of
the environmental features of the Watchung landscape in recent
years.
The map “Physiographic Regions of New Jersey” at left
shows the general location of the area you will study. The
concentric ridges, indicated by the shaded areas, are the
Watchung Mountains which are part of the Appalachian
Highlands. These ridges contrast sharply with the low-lying
country between and beyond them, which is dotted on the
map.
The ridges of the Watchung Mountains are composed of a
volcanic rock called basalt. Basalt is a very hard and
massive type of rock which is not easily worn down by the
forces of erosion. The areas between and around these
basalt ridges are composed of a very different kind of rock
– shale. Shale is much softer and more easily worn away
than basalt. Thus, the basalt areas have remained as high,
steep ridges while the shale areas have worn down over
many millions of years into low-lying, level expanses. The
cut-away diagram of “The Watchung Mountains” on the
next page shows that the steep ridges of the mountains are
formed by slanting layers of basalt sandwiched between
worn-down shale layers.
The difference in hardness between shale and basalt
accounts not only for the contrasting landforms produced
by them but also for differences in the soils associated with
the two kinds of rock. Because basalt is so hard and dense,
it is not readily affected by the processes of weathering.
In weathering, rocks are decomposed and broken apart into
small fragments. Weathering usually changes rocks into
fine, loose matter from which soils are formed. Basalt
breaks up very slowly and produces only thin, stony soils.
Also, what little loose material it does produce is easily
eroded – that is, carried away by water flowing down the slope, or by sliding off the steep slopes.
By contrast, the softer shale provides an excellent base for soil formation. Weathering of shale produces
large amounts of fine particles. These are not subject to such rapid erosion as in basalt areas, since shale
areas tend to be fairly level. So the soils which have formed over the shale areas are deeper and less stony
than the soils in the basalt areas. When farmed they are more productive than the soils in the basalt areas.
How do these closely intertwined physical characteristics and processes affect the choice of locations for
certain human activities? In this activity you will be making location predictions for different types of
activities. To prepare for this, think about the following questions:
1)
2)
3)
4)
5)
6)
Does steepness of slope affect the choice of location for farming?
Which type of area, basalt or shale, would have the best soils for farming?
In which type of area would it be easiest to use farming machinery?
In which type of area would it be easiest to build houses and farm buildings?
In which type of area would it be easiest to obtain water? Why?
Part of the Watchung area is covered with forests. Would you expect the forests to be mainly on the
basalt areas or mainly on the shale areas?
7) Do steep slopes affect the location of roads? How?
8) What factors are important in deciding the particular routes of main highways?
9) Which type of area, basalt or shale, would be best for the construction of industrial plants?
10) Which type of area would be best for urban development?