Geology of Middlesex County

Roadside Geology of Massachusetts. James W.  Skehan. Copyright 2001, Mountain Press Publishing Company. Pg 176-177
http://www.lsrhs.net/departments/science/faculty/brandesa/glacier.html
http://www.homepage.montana.edu/~geol445/hyperglac/glossary.htm
http://www.priweb.org/ed/TFGuide/NE/geo_history/geologichistory.pdf
http://www.emporia.edu/earthsci/student/martin1/laurentide.html
http://www.homepage.montana.edu/~esci111/111glacierlab/LGM%20deglaciation.jpg
http://www.emporia.edu/earthsci/student/martin1/laurentide.html
http://www.newenglandtravelplanner.com/go/ma/boston_west/concord/sights/walden_ecology.html
http://www.answers.com/topic/glacial-lake
http://mail.colonial.net/~hkaiter/wxerosglacier.html
http://www.earthsciences.ca/arctic/arrowsmith_river/default.htm
http://www.cgq-qgc.ca/tous/esker/esker-anglais.html