Why are the tops of mountains round and the soil often rough, rocky, and thin in many places in the northeast?

the early settlers abused and overused the land.
glaciers scoured the landscape, grinding the high places and mixing the soil with rocks.
the indian population purposely destroyed the countryside when they discovered the white settlers would not leave.
during the past three centuries, the urban dwellers in the area have appropriated the fine soil for the cities.

The mountains that you are describing are the Appalachians, which are the oldest mountains in North America that are present today. Due to millions of years of erosion from glaciers, wind, water and seismic activity, the Appalachians were rendered into hilly and rounded mountains, with the rough, rocky, and thin soil being mostly of sedimentary rock that was eroded from the mountains.

May consider a group  g=({0,1},+)g=({0,1},+)where  ++  will work as the xor operator like we work in boolean algebra. note here, that ‘00’ and ‘11’ are not the usual 0 and 1 that we work with everyday. the elements are  called  ‘00’ and ‘11’ and  may not mean  zero (nothing) and one (single). ‘00’ is the identity for the given binary operator +, meaning that any element operated with ‘00’ gets us that element itself.  for a set  ss  in  g′g′  having more elements than just  {0,1}{0,1}  the values for  a+b∈sa+b∈s, such that  a∈s,b∈sa∈s,b∈s, have to be first defined, only then can you determine the value of  1+11+1. the answer could possibly have been  22  if oanswer is25,000

Ithink it is space that makes up 70 percent