OF THE BUREAU OF ETHNOLOGY. XXVII 
Col. Mallery’s studies in pictography commenced in the 
field. He was stationed with his military command at Fort 
Rice, on the upper Missouri river, in the autumn of 1876, and 
obtained a copy of the remarkable pictograph which he then 
called ‘A Calendar of the Dakota Nation,” and published under 
that title, with interpretation and explanation, in Vol. 11, No. 1, of 
the series of bulletins of the U.S. Geological and Geographical 
Survey of the Territories, issued April 9, 1877. This work at- 
tracted attention, and at the request of the Secretary of the 
Interior he was ordered by the Secretary of War, on June 13, 
1877, to report for duty, in connection with the ethnology of the 
North American Indians, to the present Director of this Bureau, 
then in charge of the Geographical and Geological Survey of 
the Rocky Mountain Region. Upon the organization of the 
Bureau of Ethnology, in 1879, Col. Mallery was appointed eth- 
nologist, and has continued in that duty without intermission, 
supplementing field explorations by study of all accessible 
anthropologic literature and by extensive correspondence. His 
attention has been steadily directed to pictography and to sign- 
language, which branches of study are so closely connected 
that neither can be successfully pursued to the exclusion of 
the other, but his researches have by no means been confined 
to those related subjects. 
The plan and scope of the present work may be very brieily 
stated as follows: 
After some introductory definitions and explanations general 
remarks are submitted upon the grand division of petroglyphs 
or pictures upon rocks as distinct from other exhibitions of 
pictography. This division is less susceptible of interpretation 
than others, but it claims special interest and attention because 
the locality of production is fixed, and also because the an- 
tiquity of workmanship may often be determined with more 
certainty than can that of pictures on less enduring and readily 
transportable objects. Descriptions, with illustrations, are 
presented of petroglyphs in North America, including those 
in several provinces of Canada, in many of the states and 
territories of the United States, in Mexico, and in the West 
Indies. A large number from Central and South America 
