Is located about 8 miles southwest from Banner on the Cuyamaca grant, belonging to the Waterman estate. The Superintendent, Waldo S. Waterman, informed the writer that nothing of special interest had been developed in the mine since the publication of the last report (1890). MESA GRANDE DISTRICT. A few miles to the northwest from Julian is located the Mesa Grande District, where lenses of a yellowish pellucid quartz of semi-granular texture have been developed somewhat. All of this quartz contains gold, and some of it is quite rich; but nothing of consequence has been done of late, further than to organize a stock company. ESCONDIDO MINES. Near the flourishing little town of Escondido are some old Mexican mines, which have been acquired by a San Diego company. The veins are gold-bearing, the quartz having formerly been worked in arrastras with evidently good results, as the surface workings are quite extensive. Within the past two years, however, little has been done on the property. PINE VALLEY. The Pine Valley Mines lie 6 miles from the Stonewall and San Diego Stage road, the nearest station being Descanso. Two mills, one of five and one of two stamps, crush the rock taken from the veins in the vicinity. This quartz, it was claimed, would mill over $50 per ton. The veins occur in a formation similar to that about Julian and Banner. REPORTED TIN DISCOVERIES. Frequently there have been rumors of the discovery of tin stone in San Diego County, but up to this time no such ores are known to exist outside of the property known as the Temescal Mines, which are located on the line of San Bernardino and San Diego Counties. However, in the large crystalline area which extends over a considerable portion of San Diego County, it would not be strange to find tin stone under conditions similar to those which obtain in the Harney Peak region in the Black Hills of Dakota. There the cassiterite is found in good-sized crystals and finely disseminated grains in a matrix of coarse-grained granite, which has been thrust up through the schists in the form of intrusive dikes of greater or less size. It usually is associated with tourmaline, wolfram, and other black minerals, making it difficult to distinguish it without making a test of some sort. The search for tin in San Diego County has been confined to looking for a black rock similar to that found in the Cajalco Mine. DULZURA DISTRICT.