Works Cited
Blackley, Ronald, ed. "Precambrian climate." nps.org. northernarizona department of geology, 2 Sept. 2010. Web. 11 Dec. 2014.
live.science. perch, 2 Aug. 2013. Web. 11 Dec. 2014.
pbs.org. clearblueskyspublication, 2001. Web. 11 Dec. 2014.
"Precambrian Time." science.natinolgeografic. national geografic society, 1996. Web. 6 Nov. 2014.
Rossana and calvin, ed. "Palezoic Era." science views. jason hamilton, n.d. Web. 8 Nov. 2014.
Blackley, Ronald, ed. "Precambrian climate." nps.org. northernarizona department of geology, 2 Sept. 2010. Web. 11 Dec. 2014.
live.science. perch, 2 Aug. 2013. Web. 11 Dec. 2014.
pbs.org. clearblueskyspublication, 2001. Web. 11 Dec. 2014.
"Precambrian Time." science.natinolgeografic. national geografic society, 1996. Web. 6 Nov. 2014.
Rossana and calvin, ed. "Palezoic Era." science views. jason hamilton, n.d. Web. 8 Nov. 2014.