The following is the organization of the army in its march from Puebla to the City of Mexico:

GENERAL STAFF.

Lieutenant-Colonel Ethan Allen Hitchc.o.c.k, a.s.sistant Inspector General.

Captain Henry Lee Scott, Acting Adjutant General.

First-Lieutenant T. Williams, Aid-de-camp.

Brevet First-Lieutenant George William Lay, Aid-de-camp.

Second-Lieutenant Schuyler Hamilton, Aid-de-camp.

Major J.P. Gaines, Volunteer Aid-de-camp.

ENGINEER CORPS.

Major John Lind Smith, Chief; Captain Robert Edward Lee; Lieutenants Pierre Gustave Toutant Beauregard, Isaac I. Stevens, Zealous Bates Tower, Gustavus Woodson Smith, George B. McClellan, John Gray Foster.

ORDNANCE DEPARTMENT.

Captain Benjamin Huger, Chief, with siege train.

First-Lieutenant Peter Valentine Hugner.

Second-Lieutenant George Thom.

Brevet Second-Lieutenant E.L.F. Hardcastle.

QUARTERMASTER'S DEPARTMENT.

Captains James R. Irwin, Chief; Abraham C. Myers, Robert Allen, Henry Constantine Wayne, Justus McKinstry, George W.F.

Wood, J. Daniels, O'Hara, Samuel McGowan.

SUBSISTENCE DEPARTMENT.

Captain John Breckinridge Grayson, Chief.

Captain Thomas P. Randle.

PAY DEPARTMENT.

Major Edmund Kirby, Chief.

" Abraham Van Buren.

" Albert Gallatin Bennett.

MEDICAL DEPARTMENT.

Surgeon-General Thomas Lawson; Surgeons Benjamin Franklin Harney, Richard Smith Satterlee, Charles Stuart Tripler, Burton Randall, James Meck Cuyler; a.s.sistant Surgeons Alexander F. Suter, Josiah Simpson, David Camben De Leon, Henry H. Steiner, James Simons, Joseph K. Barnes, Levi H. Holden, Charles Carter Keeney, James Frazier Head, John Fox Hammond, Josephus M. Steiner, Charles P. Deyerle, Ebenezer Swift.

Surgeons J.M. Tyler, volunteer; McMillan, volunteer; Courtney J. Clark, volunteer; W.B. Halstead, volunteer. a.s.sistant Surgeons R. Hagan, volunteer; H.L. Wheaton, volunteer. Surgeons R. Ritchie, First Volunteers; J. Barry, First Volunteers; Edwards, First Volunteers; L.W.

Jordan, First Volunteers; R. McSherry, First Volunteers; Roberts, First Volunteers.

CORPS.

Colonel Harney's Brigade.

Detachment of First Light Dragoons, Captain James Kearny.

Detachment of Second Light Dragoons, Major Edwin Vose Sumner.

Detachment of Third Light Dragoons under Major Andrew Thomas McReynolds.

I. BREVET MAJOR-GENERAL WORTH'S DIVISION.

1. Colonel John Garland's Brigade.

Second Regiment of Artillery, serving as infantry.

Third " " " " "

Fourth " " Infantry.

Duncan's Field Battery.

2. Colonel Andrew Clark's Brigade.

Fifth, Sixth, and Eighth Regiments of Infantry.

A Light Battery.

II. BREVET MAJOR-GENERAL TWIGGS'S DIVISION.

1. Brevet Brigadier-General Persifor F. Smith's Brigade.

Rifle Regiment.

First Regiment of Artillery, serving as infantry.

Third Regiment of Infantry.

Taylor's Light Battery.

2. Colonel Bennet Riley's Brigade.

Fourth Regiment of Artillery, serving as infantry.

First Regiment of Infantry.

Seventh Regiment of Infantry.

III. MAJOR-GENERAL GIDEON J. PILLOW'S DIVISION.

1. Brigadier-General G. Cadwallader's Brigade.

Voltigeurs.

Eleventh and Fourteenth Infantry.

A Light Battery.

2. Brigadier-General Franklin Pierce's Brigade.

Ninth, Twelfth, and Fifteenth Infantry.

IV. MAJOR-GENERAL JOHN A. QUITMAN'S DIVISION.