usually attained by gradual evolution. Worthy of record, however, is the additional knowledge gained on the genesis and distribution of the copper deposits of southeastern Alaska by C. W. Wright, and on the tin and other metal-bearing lodes of Seward Peninsula by Adolph Knopf. L. M. Prindle's studies in the Yukon-Tanana region point. to the conclusion that large batholithic masses of intrusive rocks are there mantled by a comparatively thin shell of metamorphic sediments and that the gold deposits are closely connected with the intrusions. W. W. Atwood's investigations indicate that there was more than one extensive period of base-leveling in the Yukon basin. In Seward Peninsula Messrs. Smith and Katz have obtained evidenceof exceedingly intricate folding of the metamorphic sediments of the Nome group. The Chitistone limestone in the Copper River region, long believed to be Carboniferous, has been proved to be Triassic by fossils collected by Messrs. Moffit and Maddren and determined by T. W. Stanton. This adds at least 4,000 feet of strata, and probably double that amount, to the Triassic section of central Alaska. The report on the geology and mineral resources of the Controller Bay region, by G. C. Martin (Bulletin 337), describes the geography and the bed-rock, glacial, and economic geology of this region, which lies on the Pacific coast of Alaska between meridians 143° 45′ and 144° 40'. Most of the bed-rock formations fall into two groups, one of which is known to be Tertiary (Miocene?), and the other is probably Tertiary. There is also a small area of metamorphic rocks of unknown age. The sediments are closely folded and profoundly faulted. Igneous rocks are represented solely by a few dikes. The mineral resources include some oil seepages, with two wells that have made a small production. Of far greater importance are the coal beds. These coals are anthracite and semibituminous and include some coking coals. They are known to underlie an area of 56.4 square miles, and the field probably extends to the northeast, beyond the area mapped. DIVISION OF MINERAL RESOURCES. The work of the division of mineral resources consisted in the preparation of reports on the mineral resources of the United States for 1906 and 1907. The report for 1906 was completed, published, and distributed, and the report for 1907 was prepared in part, seventeen chapters of it having been completed before the close of the fiscal year 1907–8 and transmitted for publication separately in advance of the volume. The chapters on aluminum and bauxite, cement, asbestos, monazite and zircon, and phosphate rock were printed and distributed before June 30, and the manuscript for the reports on asphalt and bituminous rock, barytes, anthracite coal, fluorspar and cryolite, fuller's earth, gypsum, manganese ores, mica, mineral paints, salt and bromine, tin, and slate was submitted for publication. The production statistics for many other minerals were announced to the press for publication in advance of the full report. Waldemar Lindgren, geologist in charge of economic geology of metalliferous ores (except iron), has given about one-half of his time to the administrative work on the same subjects for this division. During July and August, 1907, Mr. Lindgren spent some time in the Denver office, having been detained in that city as witness in the suit instituted by the postal authorities against the Lost Bullion Mining Company of New Mexico. During March and April Mr. Lindgren made a tour of inspection covering the three suboffices, San Francisco, Salt Lake City, and Denver. Congress having failed to make specific appropriations for continuing the investigation of the black sands of the Pacific coast and other portions of the United States, this investigation was discontinued July 1, 1907. A considerable part of the time of the experts employed in this division is consumed in answering technical inquiries and making visual examinations of mineral specimens that are submitted by numerous persons for determination. Inquiries for information as to the character of ores are answered as promptly as possible, and such information is given freely where a chemical analysis or assay is not required. DIVISION OF CHEMICAL AND PHYSICAL RESEARCH. In the physical laboratory George F. Becker continued his investigations on geophysical problems, with particular reference to their application to geology. C. E. Van Orstrand has remained in immediate charge of the work on elasticity. In addition to theoretical investigations and the reduction of observations made at the Washington Monument, systematic observations have been made on the elastic after-effect of steel tapes maintained at a constant temperature. The problem presents many difficulties from either a theoretical or an experimental standpoint; but the possibility of its application to a precise discussion of the stress-strain relation, the variation of electric resistance, the condition of isostasy which probably exists in the crust of the earth, the internal resistances of solids, etc., would seem to justify a general investigation of high precision. A few experiments on the diffusivity of solid metals are being conducted, partly with the hope of throwing some light on the mechanism of the elastic after-effect, but chiefly for the purpose of investigating a very interesting property of matter which has hitherto received but little attention from scientific men. The following publications indicate the scope of these investigations: Becker, G. F., Current theories of slaty cleavage. (Am. Jour. Sci., July, 1907.) Becker, G. F., and Van Orstrand, C. E., Tables of hyperbolic functions. (Now in course of publication by the Smithsonian Institution.) Van Orstrand, C. E., Inverse interpolation by means of a reversed series. (Philos. Mag., May, 1908.) Becker, G. F., Age of a cooling globe in which the initial temperature increases directly as the distance from the surface. (Science, February 7, 1908.) Becker, G. F., Relations of radioactivity to geology and cosmogony. (Bull. Geol. Soc. America.) In the chemical laboratory during the year 116 quantitative analyses were reported, and also 826 qualitative determinations, chiefly of minerals sent for examination by persons not connected with the Survey. F. W. Clarke completed and published during the year his bulletin (No. 330) entitled "The data of geochemistry." He also published a paper on the composition of two marine sediments-the average" red clay " and the intermediate terrigenous clay. W. F. Hillebrand published an important paper on vanadium minerals from Peru, and a joint paper with W. T. Schaller on the mercury minerals of Texas. He also made a considerable number of analyses of lead bullets, furnishing data for use of the United States Senate committee in the Brownsville investigation. He conducted and completed an investigation on the determination of ferrous iron and water in rock analyses. E. C. Sullivan continued his work on the chemistry of ore deposition until April 1, when he severed his connection with the Survey, having accepted an invitation to engage in work for a private firm. George Steiger, whose time was largely occupied with routine work, completed and published the results of two investigations on analytical methods, one on a new form of colorimeter and the other on the estimation of small quantities of fluorine. He also did some work on the dehydration of gypsum and on the precipitation of zirconium as phosphate. W. T. Schaller, in addition to his necessary routine work, including a large number of mineral determinations, published several papers on mineralogical subjects. A paper by Messrs. Hillebrand and Schaller on the mercury minerals from Terlingua, Tex., is nearly ready for publication as a bulletin of the Survey. TOPOGRAPHIC BRANCH. ORGANIZATION. The organization of the topographic branch remained the same as at the close of the last fiscal year until January 18, 1908, when R. B. Marshall was appointed chief geographer and T. G. Gerdine succeeded Mr. Marshall as geographer in charge of the Pacific division. The organization is as follows: Atlantic division, Frank Sutton, geographer in charge. Rocky Mountain division, E. C. Barnard, geographer in charge. Inspectors of topography, J. II. Renshawe, geographer; W. M. Beaman and F. E. Matthes, topographers. E. M. Douglas, geographer in charge of office prior to the appointment of the chief geographer, retains immediate supervision of the computing and instrument sections, and is in general charge of the office administration of the topographic branch in the absence of the chief geographer. During April, May, and June Mr. Douglas was in charge of the survey of the boundary of the Luquillo National Forest in Porto Rico. Henry Gannett, geographer, was absent on leave during the whole year while assistant director of the Cuban census. PERSONNEL. The technical corps of the topographic branch was increased during the year by the appointment of 16 junior topographers, 4 assistant topographers, and 1 draftsman. It was reduced by death, transfers, and resignations amounting to 12. With these changes the technical force now includes a chief geographer, 9 geographers, 40 topographers, 38 assistant topographers, 4 topographic aids, 20 junior topographers, and 4 draftsmen. Four of the topographers and 1 geographer are on leave without pay. In addition to the above regular force 167 technical field assistants were employed during the whole or a part of the field season. SUMMARY OF RESULTS. The condition of topographic surveys to July 1, 1908, distinguished as to scale, etc., is shown on Pl. II. As shown in the following tables, which give the details of topographic mapping and spirit leveling for the fiscal year, the total area mapped was 25,658 square miles, making the total area surveyed to date in the United States 1,051,126 square miles, or about 35 per cent. In addition, 6,979 square miles of revision or resurvey were completed, making the total area of actual surveys for the season 32,637 square miles. Triangulation and primary-traverse stations to the number of 504 were occupied, located, and marked and 19 were intersected, and 3,468 miles of primary traverse were run. In the course of this work 35,325 square miles were covered by primary control. In connection with these surveys 7,543 linear miles of primary levels and 843 miles of precise levels were run, making the total amount of primary and precise spirit leveling done since the authorization of this work by Congress, in 1896, 212,149 miles. The area covered by topographic surveys in Alaska during the fiscal year 1907-8, as reported in detail on pages 40-43, was about 6,626 square miles, 501 of which were mapped for publication on the scale of 1: 62,500 and 6,125 for publication on the scale of 1:250,000. |