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the profiles taken by the topographer with the solar transit (Gurley's). The large map has been constructed from the vertical and horizontal angles observed along these lines at short intervals, the intervening topography having been sketched in. In a few instances (over small areas which could not be covered by our lines in the limited time allowed us), the topography has been worked in from the sheets of the United States Geological Survey, but in every case of this kind I have personally gone over the tracts and satisfied myself that those portions of the sheets are reliable, or I have had the inaccuracies corrected by special work with the compass. The result is a topographic map much more accurate than any hitherto published, and one which is suited to the correct delineation of the geology as far as we have been able to carry our studies. The monuments of the United States Geological Survey Geodetic Corps have been placed with precision, and these have furnished valuable checks upon our work. The field notes, including the geology, were all plotted first upon the scale of one thousand and forty feet to the inch, reduced by pantograph to 1/62500 , and this again reduced in the office to 1/125000 and carefully drawn for further reduction by photography, the engraving being upon the scale of 1/250000 or three and nine-tenths miles to the inch. The geology was worked up in detail along the transit lines, which were usually laid out with reference to the structure, and many complicated areas were thus studied minutely. Contacts of the different terranes have been instrumentally run as far as has been possible, and details of this character which can not be given from actual knowledge are shown upon the map in broken or dotted lines. Subsidiary topography was also largely worked out by the compass.

The geologic conclusions tentatively announced by myself in the First Annual Report are mostly confirmed by subsequent work in the field.

Besides the results announced in my accompanying report, there remains a large amount of partially elaborated material, and some which is in a more advanced stage of preparation, but which could not be arranged and edited in time to appear therewith. A series of thin slices of our crystalline rocks is being made in the laboratory, and some exchanges with other workers have given us a fair beginning in this department.

The fossils obtained from the Cambrian, Silurian, and possible Devonian strata have been given a preliminary examination, but little more can be done with them until more complete collections can be secured. A table of the minerals of my district, with ample notes of localities, modes of occurrence, special characteristics and economic relations, is so far advanced that its publication as a Bulletin might be feasible at an early date.

The recent discovery of tin ores by myself necessitated a special trip to Llano and Mason counties in November. With Mr. Ellsworth as assistant, I