﻿190 Cincinnati Society of Natural History. 



the manner of rafters ; the thrusting weight is transmitted to the abut- 

 ments ; all that was wanting was the keystone to complete the perfect 

 arch. (Fig. 3.) 



Figure 3,— STONE BRIDGE.— From Lord Kingborough's Mexican Antiquities. 



The wheel sculptured stones are numerous. They all agree with the 

 Calendar Stone, in having eight pointed rays and eight blunted rays, di- 

 viding the circumference into sixteen equal parts. 



i <E5 



Figure 4. — The three arrows of Chapultepec. J. W. A. 



There were also some very interesting stones found on the hill of Chapul- 

 tepec, one of which had three arrows engraved upon its horizontal surface. 

 The points of the arrows directed toward the east marked out the two 

 solstitial points, and the middle arrow, which bisected the angle between 

 the two others, pointed due east, to the equinoxial point ; at the common 

 point of intersection of the three arrows, there was a band which tied them 

 together. There was observed a small line crossing its centre, and two 



