[Footnote 5: Century Magazine, October, 1890, vol. XL, No. 6, p. 806 et seq.] In recent years several publications have appeared which, while not bearing directly on the De Chelly ruins, are of great interest, as they treat of analogous remains--the cliff ruins of the Mancos canyon and the Mesa Verde. These ruins were discovered in 1874 by W. H. Jackson and were visited and described in 1875 by W. H. Holmes,[6] both of the Hayden Survey. This region was roamed over by bands of renegade Ute and Navaho, who were constantly making trouble, and for fifteen years was apparently not visited by whites. Recent exploration appears to have been inaugurated by Mr F. H. Chapin, who spent two summers in the Mesa Verde country. Subsequently he published the results of some of his observations in a handsome little volume.[7] In 1891 Dr W. R. Birdsall made a flying trip to this region and published an account[8] of the ruins he saw the same year. At the time of this visit a more elaborate exploration was being carried on by the late G. Nordenskioeld, who made some excavations and obtained much valuable data which formed the basis of a book published in 1893.[9] This is the most important treatise on the cliff ruins that has ever been published, and the illustrations can only be characterized as magnificent. All of these works, and especially the last named, are of great value to the student of the cliff ruins wherever located, or of pueblo architecture. [Footnote 6: U.S. Geol. Survey, F. V. Hayden in charge; 10th Ann. Rept. (for 1876), Washington, 1878.] [Footnote 7: The Land of the Cliff Dwellers, by Frederick H. Chapin; Boston, 1892.] [Footnote 8: Bull. Am. Geog. Soc., vol. XXIII, No. 4, 1891; The Cliff Dwellings of the Canons of the Mesa Verde.] [Footnote 9: The Cliff Dwellers of the Mesa Verde, by G. Nordenskioeld; Stockholm and Chicago, 1894.] GEOGRAPHY The ancient pueblo culture was so intimately connected with and dependent on the character of the country where its remains are found that some idea of this country is necessary to understand it. The limits of the region are closely coincident with the boundaries of the plateau country except on the south, so much so that a map of the latter,[10] slightly extended around its margin, will serve to show the former. The area of the ancient pueblo region may be 150,000 square miles; that of the plateau country, approximately, 130,000.