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brown coal beds, of the deposits of iron ore, the clays, etc., and for this reason their bearing on economic geology is very pronounced.

When, however, the rocks are of eruptive origin, or have been subjected to metamorphism, and contain no fossils, they must be classified and arranged by their petrographic and mineralogical characters. The investigation of these characteristics is carried on by the study of the rocks in their natural state or macroscopically, by cutting slices of them and grinding them extremely thin so their structure can be studied with the microscope, and by separating the constituent minerals by means of their different specific gravities, and determining them by examination and chemical analysis. Such investigations also include the study of all the minerals as such.

Therefore, in order that our progress shall be at once rapid and certain, all of these points must be provided for and all be worked in unison toward a definite end — the acquirement of definite, accurate, and extended information regarding the geology of the State and its resources of minerals, soils, and waters.

WORK OF THE FOURTH YEAR,

TOPOGRAPHY

The only topographic work done in the State during the past year was that of the United States Geological Survey and the Coast and Geodetic Survey.

CO-OPERATION OF THE UNITED STATES GEOLOGICAL SURVEY.

The following report of the work done by the United States Geological Survey during the year 1892 was kindly furnished by Captain R. U. Goode:

Work was prosecuted in Texas during past field season by two parties of U. S. Geological Survey as follows: One triangulation party under Charles F. Urquhart, with H. H. Chumlea as assistant; and one topograpical party under W. B. Corse, with R. B. Robertson as assistant. These parties did not commence field operations until about September 1, having been delayed by the late passage of the appropriation bills by Congress.

In order to comply with the provisions of the Sundry Civil Bill after