from 1881 to 1884 he was almost continuously at work opening prehistoric mounds and graves in the states of Tennessee, Arkansas, Indiana, North Carolina, Georgia and Alabama.
In the latter part of 1885 he was sent to southern Florida to make a collection of corals, echinoderms, mollusca and other invertebrates for the approaching exposition at New Orleans. He gathered a wealth of valuable material, which, after the closing of the Exposition, became the property of the United States National Museum.
He was sent once more to the southwestern region of the United States, where he made a very complete collection of material illustrating the arts of the Cocopa, Pima and Yuma Indians. Much of his material was of an ethno-botanic nature, including a long list of food-plants, medicinal plants, fiber plants, etc., of the Indians, together with notes on the methods of cooking, brewing, extracting fibers, basket-making and the like.
Much pleased with Dr. Palmer's success. Professor Baird, director of the U. S. National Museum, decided to send him to the mountains of southwestern Chihuahua, a part of the western Sierra Madre of Mexico, for the purpose of studying the Tarahumara Indians of that region, an interesting tribe inhabiting caves and dwellings of the most primitive kinds; with the object of comparing them with the Cliff Dwellers of Arizona and New Mexico. Letters were sent to Governor Alexander R. Shepherd, then vice-president and general manager of the Silver Mining Company at Batopilas, informing him of Dr. Palmer's purposed visit, and asking such assistance as Governor Shepherd might be willing to give him in the prosecution of his work. Professor Baird's request met with a cordial and prompt response from Governor Shepherd, who did everything in his power to aid him.
Much botanical work was done in the immediate vicinity of Batopilas, especially at the Hacienda de San Miguel, situated at an altitude of 1,600 feet above the sea-level, the Hacienda San José, about twenty-five miles farther down the narrow gorge of the Rio Batopilas; at the Cumbre, or summit of the ridge above Batopilas, 8,850 feet above sealevel, where he found columbines, lupines, Gaultheria, gentians, alders, and Ceanothus; and at the Indian village of Norogachic, about 150 miles north of Batopilas, in the Sierra Madre, at an elevation of about 8,500 feet. This place is surrounded by mountain peaks more or less covered by junipers, madronos, manzanillas, pines and oaks, with a considerable snowfall during the winter months.
Among the plants collected in this region several proved to be new to science, and many were of economic importance. A list of them was published by Sereno Watson in the Proceedings of the American Academy, Vol. 21, 1886. The ethnological material was sent to the U. S. National Museum.