16 BUREAU OF AMERICAN ETHNOLOGY [bull. 76 



undeniably of such age as to antedate the possible appearance of 

 man upon the scene. This is not assured until the excavation has 

 reached the original floor, which may be either the bed-rock or the 

 clay left by the eroding stream when its volume had become so 

 diminished from any cause that it was no longer able to keep its 

 channel cleared out. Unless a cave is almost perfectly drj^ — and 

 few of them are — the bottom can not be reached until all standing or 

 soil water has been drained off. 



Notwithstanding the most explicit directions, a stranger without 

 a guide is frequently unable to find a cave unless its position is 

 plainly visible from some well-defined spot. The winding valleys 

 and the multitude of ravines sometimes bewilder even those living 

 among them. 



A few definitions of terms, or explanations of statements in the 

 report, may prevent misunderstanding. 



" Refuse," " signs," " indications," "evidence," referring to habi- 

 tation or occupancy, mean mussel shells; animal bones; burned or 

 worked stones; broken pottery; wrought objects of bone or shell; 

 flint implements, chips, or spalls ; ashes ; charcoal ; in short, the ma- 

 terial ordinarily found on the site of an Indian village, some or all 

 of which are to be seen Mdiere the caverns have been used for shelter. 



" Daylight " or " in daylight " is the greatest distance within the 

 entrance to a cavern at which common print raaj be easily read or 

 the nature of small objects lying on the floor determined with cer- 

 tainty. 



" Drip rock," " cave rock," or " cave formation " are general terms 

 including stalactite or stalagmite; also deposits of similar origin 

 coating the walls. Not all of these may be present in the same 

 cavern. 



" Eoof dust" is a substance, literally "lime sand," produced by 

 the superficial disintegration of the roof or walls. This process is 

 greatl}' accelerated where lichen or rock moss has gained a root 

 hold on the stone. Roof dust in a dry cavern is the equivalent of 

 stalagmite in a wet one. 



" Cave earth " is the loose, loamy material usually found in the 

 front chambers of large caverns. It is made up of roof dust, sand, 

 and silt washed from the interior, outside dust and vegetable matter 

 blown in by the wind, with minute amounts of clay or soil carried 

 in by animals. 



" Gravel " in a cavern is seldom noticeably water- worn, but is 

 the angular debris resulting from the continued fragmentation of 

 chert nodules released by erosion of the limestone. 



A "rock shelter," or " shelter cave," is a room or recess formed by 

 atmospheric erosion in the face, usually at the base, of a cliff. The 

 depth from front to back, under the projecting or overhanging 



