Roman Marble or Greek Stone?

[caldrail]

Augustus made the proud boast that he found Rome in brick and left it in marble. A prosperous period then with plenty of beautification and redevelopment going on. Brick was and would be afterward an important building material. Concrete was basis of some extraordinary roman civil engineering. But how much of these creations were truly roman in design? The arch is undeniably a sign of roman influence IMHO, but we can't discount the greek inheritance. So much of public building work is almost pure classical greek. Were roman architects attempting to recreate greek glory or was it simply a matter of copying someones elses ideas wholesale? What do you think?