76 MEXICO AND CENTRAL AMERICA 



by doorways till only pier-like sections remained, and 

 finally these piers were replaced by square or round 

 columns. The development of the Mayan temple may 

 be traced through a thousand years of change and 

 adjustment. 



Much attention was paid by Mayan builders to the 

 question of stability which was accomplished directly 

 by keeping the center of gravity of the principal masses 

 within the supporting walls rather than by the use of 

 binding stones. The cross-section of a two-roomed 

 temple of late date will illustrate how this was done. 

 There are three principal masses, one over the front 

 wall, one over the medial partition, and one over the 

 back wall. The roof where these sections join is of no 

 great thickness. The central mass is symmetrical and, 

 if the mortar has the proper cohesiveness, very stable. 

 For the front and back masses the projection of the 

 upper or frieze zone tends to counterbalance the over- 

 hang of half the vault. In the earlier temples the upper 

 zone of the fagade often slopes backward so that the 

 balance is not so perfect. 



So far we have given brief space to the question of 

 elevations. Taken vertically there are three parts to 

 the Mayan building: first, the substructure or pyra- 

 midal base; second, the structure proper; third, the 

 superstructure. In the case of temples the structure 

 proper is one story in height. Two and three stories 

 are rather common in palaces, but the upper stories are 

 in most cases built directly over a solid core and not 

 over the rooms of the lower story. The upper stories, 

 therefore, recede, so that the building presents a ter- 

 raced or pyramidal profile. One building at Tikal is 

 five stories in height, in three receding planes, the three 

 uppermost stories being one above the other. In a 

 tower at Palenque we have an example of four stories 

 but this is unusual. 



