182 REPORT OF NATIONAL MUSEUM, 1S93. 



(5) Slabs of stone, grooved, scratclied. or polislied by glacial action. 



(C) The possible economy of glacial i)roducts as shown in the utili- 

 zation of glacial bowlders for building, and the glacial clays for brick- 

 making. 



(7) The destructive effects of glaciation, as illustrated bj' tields 

 covered by drift bowlders and other glacial debris, the stripping of 

 the surface of soils, and the burial of forests: shown by photographs 

 only. 



III. LIMESTONE CAVERNS AND ASSOCIATED IMIENOMENA. 



(a) Actual plans and sections of Howe's Cave, IST. Y; the Luray 

 Caves, Va. ; Mammoth Cave, Ky., and Wyandotte Cave, Ind. 



(h) A series of photographs showing cave interiors, as follows: 

 Howe's Cave, N. Y. ; the Luray Caves, Ya. ; The Grottoes. Va. ; Mam- 

 moth Cave, Ky. ; Wyandotte and Marengo caves, Ind. 



(c) A large series of cave deposits as below, many of the stalactites 

 and stalagmites being cut and polished to show structure. 



(1) Stalactites and stalagmites from the Luray Caves and The 

 Grottoes, in Virginia. 



(2) Gypsum rosettes and incrustations from Mammoth Cave, Ky. 



(3) Gj'psum incrustations and rosettes, epsoni salt, and stalactites 

 and stalagmites, from Wyandotte, Ind. 



(4) Stalactites and stalagmites from Marengo, Ind. 



(5) Stalactites and stalagmites from the Percy and Robertson caves, 

 near Springfield, Mo. 



(6) Botryoidal stalactitic masses from caves in the Organ INiountains, 

 is^ew Mexico. 



(7) Stalactites from the Copper Queen Mines, Arizona. 



(8) Large translucent selenite crystals from a cave in Wayne County, 

 Utah. 



(9) The possible economy of cave products, shown by cut, turned, 

 and polished blocks of cave marble (stalagmite); nitrous earth, from 

 Mammoth Cave, Ky., together with a small vial of calcium nitrate 

 extracted from the same by leaching. 



(10) A series of specimens in alcohol illustrating the fauna of caves. 



(11) A small series of photographs, bone breccia and flint chips, 

 illnstrating the occupancy of caves by human beings. 



(lli) A section of a cave, some 2 by 4 feet, and 2i feet high, con- 

 structed from materials collected in Marengo, Ind., the materials 

 occnpying their original positions as taken from the cave. 



As comi)leted, the exhibit occupied two wall-cases, each some 30 

 feet in length, and three special bases carrying relief-maps and cave- 

 section. One of the most impressive and unique of these exhibits is 

 the relief map of the LFnited States, modeled by Howell, and showing 

 the restoration of tlie ice sheet of the Glacial epoch. This map is 



