The Yeomanry Mounted Division received orders on the afternoon of November 17 to move across Ajalon into the foothills and to press forward straight on Bireh as rapidly as possible.  Their trials they began immediately.  One regiment of the 8th Brigade occupied Annabeh, and a regiment of the 22nd Brigade got within a couple of miles of Nalin, where a well-concealed body of the enemy held it up.  Soon the report came in that the country was impassable for wheels.  By the afternoon of the next day the 8th Brigade were at Beit ur el Foka—­Beth-horon the Upper—­a height where fig trees and pomegranates flourish.  Eastwards the country falls away and there are several ragged narrow valleys between some tree-topped ridges till the eye meets a sheikh’s tomb on the Zeitun ridge, standing midway between Foka and Beitunia, which rears a proud and picturesque head to bar the way to Bireh.  The wadis cross the valleys wherever torrent water can tear up rock, but the yeomanry found their beds smoother going, filled though they were with boulders, than the hill slopes, which generally rose in steep gradients from the sides of watercourses.  During every step of the way across this saw-toothed country one appreciated to the full the defenders’ advantage.  If dead ground hid you from one hill-top enemy marks-men could get you from another, and it was impossible for the division to proceed unless it got the enemy out of all the hills on its line of advance.  The infantry on the right were very helpful, but the brigade on the left flank had many difficulties, which were not lessened when, on the second day of the movement, all Royal Horse Artillery guns and all wheels had to be sent back owing to the bad country.  Up to this point the fight against Nature was more arduous than against the enemy.  Thenceforward the enemy became more vigilant and active, and the hills and stony hollows more trying.  All available men were set to work to make a road for the Hong Kong and Singapore gunners, a battery which would always get as far into the mountains as any in the King’s Army.  The road parties laboured night and day, but it was only by the greatest exertions that the battery could be got through.  The heavy rain of the 19th added to the troubles.  The 8th Brigade, having occupied Beit ur et Tahta (Beth-horon the Lower) early on the morning of the 19th, proceeded along the wadi Sunt until a force on the heights held them up, and they had to remain in the wadi while the 6th Mounted Brigade turned the enemy’s flank at Foka.  The 22nd Mounted Brigade on the north met with the same trouble—­every hill had to be won and picqueted—­and they could not make Ain Arik that day.  As soon as it was light on the following morning the 6th Mounted Brigade brushed away opposition in Foka and entered the village, pushing on thence towards Beitunia.  The advance was slow and hazardous; every hill had to be searched, a task difficult of accomplishment by reason of the innumerable caves and boulders capable of sheltering