The outdoor use of the above-described fireplaces on upper terraces has apparently suggested the improvement of the ground cooking pit in a similar manner. Several specimens were seen in which the cooking pit of the ordinary depressed type, excavated near an inner corner of a house wall, was provided with sheltering masonry and a chimney cap; but such an arrangement is by no means of frequent occurrence. Fig. 73 illustrates an example that was seen on the east side of Shumopavi. It will be noticed that in the use of this arrangement on the ground--an arrangement that evidently originated on the terraces--the builders have reverted to the earlier form of excavated pit. In other respects the example illustrated is not distinguishable from the terrace forms above described. [Illustration: Fig. 73. A ground cooking-pit of Shumopavi covered with a chimney.] In the discussion of the details of kiva arrangement in Tusayan (p. 121) it was shown that the chimney is not used in any form in these ceremonial chambers; but the simple roof-opening forming the hatchway serves as a smoke vent, without the addition of either an internal hood or an external shaft. In the Zuñi kivas the smoke also finds vent through the opening that gives access to the chamber, but in the framing of the roof, as is shown elsewhere, some distinction between door and chimney is observed. The roof-hole is made double, one portion accommodating the ingress ladder and the other intended to serve for the egress of the smoke. [Illustration: Plate LXXXVII. A kiva hatchway of Tusayan.] The external chimney of the pueblos is a simple structure, and exhibits but few variations from the type. The original form was undoubtedly a mere hole in the roof; its use is perpetuated in the kivas. This primitive form was gradually improved by raising its sides above the roof, forming a rudimentary shaft. The earlier forms are likely to have been rectangular, the round following and developing later short masonry shafts which were finally given height by the addition of chimney pots. In Zuñi the chimney has occasionally developed into a rather tall shaft, projecting sometimes to a height of 4 or 5 feet above the roof. This is particularly noticeable on the lower terraces of Zuñi, the chimneys of the higher rooms being more frequently of the short types prevalent in the farming pueblos of Cibola and in Tusayan. The tall chimneys found in Zuñi proper, and consisting often of four or five chimney pots on a substructure of masonry, are undoubtedly due to the same conditions that have so much influenced other constructional details; that is, the exceptional height of the clusters and crowding of the rooms. As a result of this the chimney is a more conspicuous feature in Zuñi than elsewhere, as will be shown by a comparison of the views of the villages given in Chapters III and IV. [Illustration: Fig. 74. Tusayan chimneys.]