NO. 10 NEBRASKA ARCHEOLOGY — STRONG 225 



owe them a debt of gratitude. Throughout the work Thomas L. Green, 

 the discoverer of the site, aided in every possible way, incurring both 

 our professional and our warmest personal gratitude. Preliminary 

 reports on this work have already been published. (Strong, 1932 a, 

 1933 a, b.) A complete report is being prepared by the present writer 

 and Maurice E. Kirby (Signal Butte, A Stratified Site in Western 

 Nebraska), but since this may not appear for some little time, a sum- 

 mary report on the site is included here. The great importance of the 

 Signal Butte deposits lies in the fact that they offer a long stratified 

 record of human activity in the extreme western portion of Nebraska. 

 This, in conjunction with the stratification pointed out by Sterns at the 

 Walker Gilmore site in the extreme eastern part of the State, forcibly 

 introduces the all-important element of time perspective that to the 

 present has been so lamentably lacking for major portions of central 

 and eastern North America. 



GEOLOGIC BACKGROUND 



The general nature of Signal Butte has already been discussed and 

 illustrated in the articles previously referred to (also see pi. 23, fig. i). 

 It may be added that it is a remnant of the old original surface of the 

 high plains, is given an altitude of 4,583 feet on the United States 

 Geological Survey map (Nebraska-Scottsbluff Quadrangle), and is 

 located about one-fourth of a mile from Kiowa Creek and 14 miles 

 southwest of the North Platte River. The base of the butte is com- 

 posed of Brule clay (Oligocene), over this substratum rise almost 

 sheer walls of the Gering formation (Miocene) which is capped by 

 about 2 feet of white hard-grained rock of the same formation. The 

 upper members of the Miocene formation are lacking at Signal Butte. 

 Erosion has penetrated into and through this cap rock in certain 

 places, up-ending slabs and producing some distortion. In and above 

 this broken cap rock is a bed of sand averaging about 2 feet in thick- 

 ness (fig. 29). From bottom to top there is a marked transition from 

 coarse material to fine (based on mechanical analyses). Pebbles, more 

 abundant toward the bottom than at the top, are composed mostly of 

 slabby rock material from the Gering formation. Toward the top the 

 bed grades rather abruptly into a light buff-colored silt deposit in- 

 cluding some pebbles and quartz grains (fig. 29 and pi. 23, fig. 2). It 

 is thought that this well-sorted detrital material is of Pleistocene age. 

 This point, however, can only be established by full publication of the 

 data obtained by Kirby. 



The recent deposits on Signal Butte lying above this silt and gravel 

 are composed mostly of materials weathered from the surrounding 



