Length from _A_ to _n_ 8.10 m.-- 27 ft. _n_ to _m_ 8.38 m.-- 27 ft. _m_ to _o_ 2.51 m.-- 8 ft. _o_ to W. corner of _L_ (estimated) 5.00 m.-- 16 ft. W. corner of _L_. to _p_ 16.17 m.-- 53 ft. _p_ to _y_ 2.10 m.-- 7 ft. _y_, southward, to line _g g_ 33.44 m.--110 ft. passage-way N .00 m.-- 6 ft. 6 in. Width of western section of W. wing (about) 7.48 m.-- 25 ft. Length of south wing 13.00 m.-- 43 ft. 28 transverse walls à .28 m.--11 in. 7.84 m.-- 26 ft. ---------------- 106.02 m.--348 ft. 6 in. Width of S. wing 27.25 m.-- 90 ft. Passage _R_ 4.00 m.-- 13 ft. From _R_ to _f_ (about) 4.00 m.-- 13 ft. Line _f f_ 15.73 m.-- 52 ft. 8 longitudinal walls à .28 m.--11 in. 2.24 m.-- 7 ft. ---------------- Total length to _f_, my point of departure 53.22 m.--175 ft. ------------------ Entire length of circuit of building _A_ 283.36 m.--928 ft. Adding to this 15 m.--49 ft.--for the probable periphery of mound _H_, and 64 m.--210 ft.--for the perimeter of a southern annex to the south wing, which I have not yet described, we reach a perimeter of 362 m.--1,190 ft.--in all. Comparing these figures with those given about the great ruins of the Rio Chaco by Dr. W. H. Jackson,[120] and of the pueblo of Las Animas River by my friend the Hon. L. H. Morgan,[121] it will be seen that this building, _A_, at Pecos is probably the largest aboriginal structure of stone within the United States so far described, and that it will even bear comparison with many of the aboriginal ruins of Mexico and Central America.[122] The size of the interior court can now be easily determined. It is 64 m.--210 ft.--from N. to S., and 19.28 m.--63 ft.--from E. to W. Its area covers therefore 1,235 sq. m.--13,230 sq. ft.,--or about one fourth of an acre; whereas the entire _débris_, measured as well as possible, scatter over more than two acres of ground. For the computation of the number of rooms in the whole pile, cross-sections are necessary. (Pl. V., Figs. 1-8.) The height of each story is about the same as in _B_, to wit, 2.28 m.--7 ft. 6 in. Fig. 1, section of west wing about _l l_, from west to east. Fig. 2, lines _b b_ and _a B_. Fig. 3, section of west wing along _h h_. Fig. 4, line _d d_, north, up to south line of _C_. Fig. 5, section of west wing along line _g g_. Fig. 6, line _f f_, southern boundary of east wing, and for the entire rectangle up to _E_. Fig. 7, cross-section of north wing, line _A n_, from north to south.