Journals of Congress of the United States gives a report describing the symbols and explanation for the Great Seal of the United States.
"Report on the device for a great seal (June 20, 1782)," Journals of the Continental Congress, 1774–1789. Edited from the Original Records in the Library of Congress by Gaillard Hunt, Chief, Division of Manuscripts. Vol. XXII (January 1–August 9, 1782), 338–40 (Washington, DC: Government Printing Office, 1914), 339
Copy Exad by Joseph Pearson D Secy
On the report of the secretary of the United States in Congress assembled, to whom were referred the several reports on the device for a great seal, to take order:
The device for an armorial atchievement and reverse of the great seal for the United States in Congress assembled, is as follows:
ARMS. Paleways of thirteen pieces, argent and gules; a chief, azure; the escutcheon on the breast of the American bald eagle displayed proper, holding in his dexter talon an olive branch, and in his sinister a bundle of thirteen arrows, all proper, and in his beak a scroll, inscribed with this motto, “E pluribus Unum.”
For the CREST. Over the head of the eagle, which appears above the escutcheon, a glory, or, breaking through a cloud, proper, and surrounding thirteen stars, forming a constellation, argent, on an azure field.
REVERSE. A pyramid unfinished. In the zenith, an eye in a triangle, surrounded with a glory proper. Over the eye these words, “Annuit Coeptis.” On the base of the pyramid the numerical letters MDCCLXXVI. And underneath the following motto, “Novus Ordo Seclorum.”
Remarks and explanation:
The escutcheon is composed of the Chief and pale, the two most honorable ordinaries. The pieces, paly, represent the several States all joined in one solid compact entire, supporting a Chief which unites the whole and represents Congress. The motto alludes to this Union. The pales in the Arms are kept closely united by the Chief and the Chief depends on that union, and the strength resulting from it for its support, to denote the Confederacy of the United States of America, and the preservation of their Union through Congress. The colours of the pales are those used in the flag of the United States of America. White signifies purity and innocence. Red hardiness and valour and Blue the colour of the Chief signifies vigilance perseverance and justice. The Olive Branch and arrows denote the power of peace and war which is exclusively vested in Congress. The Constellation denotes a new State taking its place and rank among other sovereign powers. The escutcheon is borne on the breast of an American Eagle without any other supporters, to denote that the United States of America ought to rely on their own virtue.
Reverse: The Pyramid signifies strength and duration. The eye over it and the motto allude to the many signal interpositions of providence in favour of the American cause. The date underneath is that of the Declaration of Independence, and the words under it signify the beginning of the new American Era, which commences from that date.