Very rarely, however, will the conditions allow the regular arrangement of gaits indicated above. Rolling country, with ascents and descents, stretches of hard or stony road or of mud, dust, or sand, crossings of streams, etc., will ordinarily impose corresponding changes of gait or pace on each of the small elements of the column as it reaches them. To provide for this the troops in route column, when so directed, take greater distances than prescribed in order to allow for closing up at checks. The commander must give this matter unremitting attention, since normal route-order distances in column frequently entail discomfort to the men and sometimes injuries to the horses which might have been avoided. Unless under exceptional circumstances, the commander of a marching column will authorize each troop commander to so regulate the gait and pace of his troop as to conform to that next in front, the gait and pace of the leading troop being regulated by the commander himself. This results in each troop changing to the trot, walk, leading dismounted, etc., at the same place at which the leading troop did, and although regulation distances, are frequently exceeded, the tendency on all stretches of good road is to close on the leading troop of the column. With care this method of marching should result in enabling each troop in the column to move with almost the same regularity and freedom from checks as though it were in the lead. The fast rate of march that can be expected of small detachments and of single riders can not be demanded of a long Cavalry column, and as the command increases in size the rate of march will decrease. The regulation gaits being, at the walk, 4 miles, the trot, 8 miles, Cavalry should be able to make, including halts, 5 miles per hour or better. This rate can be maintained for daily marches of 25 miles under ordinary conditions for a week at a time, after which a day of rest should be allowed before continuing the march. =980.= =Formations=: The habitual formation for marches is route order in column of fours (par. 754). When the roads are unsuitable or the command is small, column of twos or troopers is permissible. To economize road space in large commands =double column= or parallel columns should be used if practicable. Squadrons in regiment and troops in squadrons alternate in leading, the rule being that the one in front one day automatically follows in rear the next day. =981.= =Halts=: The first half hour of a march should be made at a walk and the first halt of 10 or 15 minutes toward the end of the first hour after starting; it should, if possible, be preceded by a short trot in order to make apparent any faulty adjustment of equipment. This halt gives an opportunity for the horses to stale and for the troopers to attend to the calls of nature, to tighten girths, and to adjust saddles, equipment, and clothing.