74 REPORT OF THE SECRETARY. 



tion between these obdurate rock masses and the topography. Many of them appear 

 in oniineuces or in the extremities of salients juttinj? streamward from the general 

 upland ; and even whore they have not been observed their existence may be sus- 

 pected in all the more sharply-cut salients. 



"'The Piedmont gneiss varies from place to place in mineral composition as well as 

 in structure, and now and then sheets or masses of steatite — the soapstone of the 

 aborigines and early white settlers— may be found. This is true within the Park as 

 well as beyond its limits, and at two points quarries have been opened for the extrac- 

 tion of those niaterials for industrial purposes. 



"The topographic configuration of the Park is well shown upon the map. The grace- 

 fully curved hills and steep ravines characteristic of the country about the National 

 Capital hero represent the work of Rock Creek during ages of erosion, and from hills, 

 valleys, and ravines the systematic geologist reads a record of erosion upon lines 

 first determined by rock structure, afterward modified by the superposition of an ex- 

 tensive formation — the Potomac — and finally developed under the influence of these 

 conditions atTected albeit by the structure of the rocks reached by the stream in the 

 latter stages of its cutting. It is by reason of the varied conditions represented in 

 this complicated history that, while the configuration is commonly adjusted to the 

 hard quartz veins, there are cases in which quartz and topography are manifestly 

 independent in their distribution. 



"The Park is watered as well as drained by Rock Creek and a few spring-born 

 streamlets. Within the reservation there are two walled springs, two others that 

 have received some attention, and a number of minor seeps; but the yield of these 

 springs is trifling, none now giving permanent streams and all threatening to diminish 

 as the surface is further deforested or trampled. Wells of small yield may doubtless 

 be found by excavating in nearly any part of the Park ; but the Potomac and Colum- 

 bia areas are too small to alford reservoirs; the dips of gneiss are too steep to give 

 strong subterranean streams, and the structure of the prevailing formation is too 

 complex to permit determination of such small subterranean water-ways as may 

 exist; moreover, wells east of Rock Creek will inevitably be contaminated within a 

 few years, if not at present, in consequence of the recent spread of population over 

 the adjacent uplands; and there is prospective danger of like contamination west ot 

 the water-way. Accordingly the Park must look either to Rock Creek or beyond its 

 own limits for permanent water supply." 



Unmistakable sigus of Indian occupation have been found. Professor Holmes, 

 the archa-ologistof the Geological Survey, made a careful examination of the bowlder- 

 beds of the Potomac formation, and found many chipped implements, showing that 

 here, as elsewhere in the Rock Creek region the quartzite pebbles are shaped into 

 weapons While most of those found were the imperfectly formed and rejected 

 stones, some portions of finished blades were discovered. It is not improbable that 

 an Indian village once existed within the Park limits, near the soapstone (juarry on 

 the eastern side of the creek. 



At the close of the fiscal year, the development and adaptation of this beautiful 

 region to the j)urposes of a zoological park were already commenced ; competent 

 ]>rofes8ional advice was procured, and plans were under consideration for accommo- 

 tlatiug the animals now in the ccdlection and those that will shortly be added. 

 Respectfully submitted. 



Frank Bakkr, 

 Acting Manager. 



Mr. R. P. Lan'Oi.ry, 



Secretary of Smithsonian Inxtitution. 



