It will be noted that the original transoms of the large openings have in all these cases been entirely filled up with masonry. [Illustration: Plate XCVIII. Cross-pieces on Zuñi ladders.] [Illustration: Fig. 93. A Zuñi doorway converted into a window.] The clearness with which all the steps of the gradual reduction of these openings can be traced in the exposed stone work is in marked contrast with the obscurity of such features in Zuñi. In the latter group, however, examples are occasionally seen where a doorway has been partly closed with masonry, leaving enough space at the top for a window. Often in such cases the filled-in masonry is thinner than that of the adjoining wall, and consequently the form of the original doorway is easily traced. Fig. 93, from an adobe wall in Zuñi, gives an illustration of this. The entrance doorway of the detached Zuñi house illustrated in Pl. LXXXIII, has been similarly reduced in size, leaving traces of the original form in a slight offset. In modern times, both in Tusayan and Cibola, changes in the form and disposition of openings seem to have been made with the greatest freedom, but in the ancient pueblos altered doors or windows have rarely been found. The original placing of these features was more carefully considered, and the buildings were rarely subjected to unforeseen and irregular crowding. In both ancient and modern pueblo work, windows, used only as such, seem to have been universally quadrilateral, offsets and steps being confined exclusively to doorways. ROOF OPENINGS.