76 ESTABLISHMENT OF A NATIONAL BOTANIC GARDEN. 



While the character of the formations is given in the map legend, 

 the following details regarding them may be useful : 



The predominating materials in the region are the sands and clays 

 of the Patapsco and Arundel formations, which comprise the medi- 

 cal portion of the Potomac group. The clay in the lower .part of 

 Hickey Valley may represent the top of the Patuxent formation or 

 lower member of the group. These sands and clays are in irregular 

 bodies, not only alternating one above the other, but also intergrad- 

 ing laterally. Owing to this relation it is not possible to map the 

 individual bodies of each material. In general, the Patapsco beds 

 consist mostly of sand and parts of this are cemented by oxide of 

 iron into layers of brown " iron stone " which are conspicuous on 

 Mount Hamilton and Hickey Hill. Detached fragments of this rock 

 also occur in many of the lower slopes and in the terrace deposits. 

 The latter are thin at most places and not everywhere distinguish- 

 able from the underlying clay or sancl. In part also they consist of 

 disintegrated local material. 



The granite gneiss bedrock is from 300 to 350 feet below the sur- 

 face under most of the region. In the overlying Patuxent formation 

 are sands and gravels which contain artesian water of excellent 

 quality and generally in large volume. This water is utilized by 

 deep wells at the Reform School and at many other places in the 

 District. 



Very truly, yours, 



Geo. Otis Smith, Director. 



United States Senate, 



Washington, March 5, 1911±. 

 Dear Mr. Olmsted : I am strongly opposed to putting the Botanic 

 Garden in Rock Creek Park because I am perfectly certain that the 

 disposition of the ground for the purposes of the Botanic Garden 

 would destroj'' the peculiar beauty of the park, which has been pre- 

 served in the admirable self-restraint exercised in the treatment of 

 the park up. to this time, and because many years of conflict for the 

 preservation of Central Park against all sorts of incursions have 

 shown me that the only safety is in beating back every invasion. 



We have had one serious weakness in New York, arising from the 

 fact that the Metropolitan Museum of Art was allowed to build in 

 the park. I think that was a mistake, although I have long been a 

 trustee of the museum and am deeply interested in it. 



In my view, we can afford to go without the Botanic Garden but 

 we can not afford to destroy the park for the purpose of having one. 

 Very sincerely, yours, 



Elihu Root. 

 Frederick Law Olmsted, Esq., 

 Brookline, Mass. 



Botanic Gardens in the United States. 



[Extract from an article by Prof. N. L. Britton. in Science. Vol. IV. Xo. 88. 180fi.] 



The first botanical garden established in America was begun by 

 John Bartram in Philadelphia in 1728. In it he placed a consider- 



