The American army lay on both sides of Charles river. The right occupied the high grounds about Roxbury; whence it extended towards Dorchester; and the left was covered by Mystic or Medford river, a space of at least twelve miles. These extensive lines could not be contracted without opening to the British general a communication with the country. For the purpose of a more distinct arrangement, the army was thrown into three grand divisions. That part of it which lay about Roxbury constituted the right wing, and was commanded by Major General Ward; the troops near Mystic or Medford river formed the left, which was placed under Major General Lee. The centre, including the reserve, was under the immediate command of General Washington, whose head quarters were at Cambridge. The army consisted of fourteen thousand five hundred men; but several circumstances combined to render this force less effective than its numbers would indicate. [Sidenote: Deficiency of the Americans in arms and ammunition.] So long had the hope of avoiding open hostilities been indulged, that the time for making preparations to meet them had passed away unemployed, and the neglect could not be remedied. On General Washington's arrival in camp, he had ordered a return of the ammunition to be made; and the report stated three hundred and three barrels of powder to be in store. A few days after this return, the alarming discovery was made, that the actual quantity was not more than sufficient to furnish each man with nine cartridges. This mistake had been produced by a misapprehension of the committee of supplies, (for the magazines were not yet in possession of military officers,) who, instead of returning the existing quantity, reported the whole which had been originally furnished by the Province. Though the utmost exertions were made, this critical state of things continued about a fortnight, when a small supply of powder was received from Elizabethtown, in New Jersey.[11] The utmost address was used to conceal from the enemy this alarming deficiency; but when it is recollected, in how many various directions, and to what various bodies, application for assistance was unavoidably made, it will appear scarcely possible that those efforts at concealment could have been completely successful. It is more probable that the communications which must have been made to the British general were discredited; and that he could not permit himself to believe, that an army without bayonets would be hardy enough to maintain the position occupied by the Provincials, if destitute of ammunition.