[at-l] links to my recent NH and PA pics

[amberchime at comcast.net (Amber Holland)]

Hi all, North America has had many glacial periods through time. As the
glaciers advanced south, they churned up the surface of the earth breaking
large chunks of rock into smaller chunks and carried them south. Depending
on how far south each glacial event went determines the type of moraine or
terminal moraine left behind when the glaciers recede.
I'd say Pennsylvania is at a latitude where many of the glaciers stopped
their advance and just hung there for several hundred years chewing up the
land and depositing smaller and smaller chunks of rock. The terminal moraine
left there would be smaller than any left to the north because of the way
glaciers carry sand, dirt, and rocks from the north to the south or from the
back to the front.
20,000 years ago was the time of the last major glacial period. Since then
the build up of the surface ground cover over the glacial scares and moraine
has been determined by a number of factors. In the Pennsylvania mountains
and the rest of the mountain areas north only a few inches of ground cover
ever developed again. So when thousands of people travel over one area (a
trail), the surface cover is displaced and what is underneath appears.
Stream beds are a good example too.
Oh, you all knew this, Amber.