Meanwhile another move was made in the Caribbean. General Miles had from the first considered Porto Rico the best immediate objective: it was much nearer Spain than Cuba, was more nearly self-sufficing if left alone, and less defensible if attacked. The War Department, on the 7th of June, had authorized Miles to assemble thirty thousand troops for the invasion of Porto Rico, and preparations for this expedition were in progress throughout the course of the Santiago campaign. Miles at the time of the surrender of Santiago was actually off that city with reinforcements, which thereupon at once became available as a nucleus to be used against Porto Rico. On the 21st of July he left Guantanamo Bay and, taking the Spaniards as well as the War Department completely by surprise as to his point of attack, he effected a landing on the 26th at Guanica, near the southwestern corner of Porto Rico. The expeditionary force to Porto Rico, however, consisted not of 30,000 men but of only about 15,000; and it was not fully assembled on the island until the 8th of August. The total Spanish forces amounted to only about 10,000, collected on the defensible ground to the north and in the interior, so that they did not disturb the disembarkation. The American Army which had been dispatched from large Atlantic ports, such as Charleston and Newport News, seems to have been better and more systematically equipped than the troops sent to Santiago. The Americans occupied Guanica, Ponce, and Arroyo with little or no opposition, and were soon in possession of the southern shores of the island. Between the American forces and the main body of the enemy stretched a range of mountains running east and west through the length of the island. San Juan, the only fortress, which was the main objective of the American Army, lay on the opposite side of this mountain range, on the northern coast of the island. The approach to the fortress lay along a road which crossed the hills and which possessed natural advantages for defense. On the 7th of August a forward movement was begun. While General Wilson's army advanced from Ponce along the main road toward San Juan and General Brooke moved north from Arroyo, General Schwan was to clear the western end of the island and work his way around to Arecibo, toward which General Henry was to advance through the interior. The American armies systematically worked forward, with an occasional skirmish in which they were always victorious, and were received with a warm welcome by the teeming native population. On the 13th of August, General Wilson was on the point of clearing his first mountain range, General Schwan had occupied Mayaguez, and General Henry had passed through the mountains and was marching down the valley of the Arecibo, when orders arrived from Washington to suspend operations.