The notched or T-shape doorway, which is quite common in the Mesa Verde ruins and in Tusayan, is not abundant in De Chelly, but some examples can be seen there. One is shown in figure 67, which illustrates the type. There is no doubt that doorways of this kind developed at a time when no means existed for closing the opening, except blankets or skins, and when loads were carried on the backs of men. It often happened that doorways originally constructed of this style were afterward changed by partial filling to square or rectangular openings. The principal doorway in the front wall of the White House proper was originally of T-shape; at some later period, but before the white coating was applied, the left-hand wing and the standard below it were filled in, leaving an almost square opening. This later filling is not uncommon in De Chelly, and is often found in Tusayan, where openings are sometimes reduced for the winter season and enlarged again in the summer. Many openings are completely closed, either by filling in with masonry or by a stone slab, and examples of both of these methods are found in De Chelly. In the third wall from the east, in the upper part of Casa Blanca ruin, there is a well-finished doorway sealed by a thin slab of stone set in mud. On the right side of the opening, about the middle, a loop or staple of wood has been built into the wall, and in the corresponding place on the left side a stick about half an inch in diameter projects. An opening into the small room west of the White House proper has a similar contrivance, and another example occurs in the front wall of the small single room in the eastern end of the ruin. Oddly enough the three examples that occur in this ruin are all found in adobe walls. This feature appears to have been a contrivance for temporarily closing openings which were provided with stone slabs, and the latter were sealed in place with mud mortar when it was desired to close the room permanently. Examples, identical even in details, have been found in the Mancos canyon, and one is described and illustrated by Chapin,[15] who states that the slab was 141/2 inches wide at one end, 151/2 at the other, and 25 inches high, with an average thickness of an inch. He mentions staples on both sides. Nordenskioeld[16] illustrates another or possibly the same example. He notes, however, an inner frame composed of small sticks and mud against which the slab rested. He thinks the notched doorways belonged to rooms most frequented in daily life, while the others belonged in general to storerooms or other chambers requiring a door to close them. [Footnote 15: Land of the Cliff Dwellers, pp. 149-150, pl. opp. p. 155.] [Footnote 16: Cliff Dwellers of the Mesa Verde, pp. 52-53, fig. 28.]