AMBERRAT--Prehistoric urinite
From: The Desert's Past--a Natural Prehistory of the Great Baisin.
Donald K. Grayson (Wash DC: Smithsonian, 1993)
William Lewis Manly and his traveling companions spent the Christmas of1849 in Death Valley. Manly's companions did not escapethe valley until mid-February, and then only because Manly and hisfriend John Rogers walked out, returning with supplies, directionsand hope....
Seventy miles northwest of Las Vegas, Manly's group passed by PapooseLake, now close to the boundary between Nellis AFBand the Nevada Test Site. Realizing that continuing west might see themdie of thirst, the small band of travelers headed south:
"we turned up a canyon leading toward the mountain.... Part way upwe came to a high cliff and in its face were niches or cavities as large as a barrel or larger, and in some of them wefound balls of a glistening substance looking somethinglike pieces of varigated [sic] candy stuck together. The balls wereas large as small pumpkins. It was evidently food ofsome sort, and we found it sweet but sickish, and those who were sohungry as to break up one of the balls anddivide it among the others, making a good meal of it, were a littletroubled with nausea afterward" (Manly 1894:126).
Manly guessed that what they had found was a food cache belonging toIndians, and was concerned that what they had done mightcause them serious problems.
"I considered it bad policy to rob theIndians of any of their food," he went on to say, "for they must bepretty smart people to live in this desolate country and find enough tokeep them alive...they were probably revengeful, and mightseek to have revenge on us for the injury" (Manly 1894:126).
The Manly party was not the only one to take notice of this "glisteningsubstance," although they may have been the only ones tomistake it for food. In 1843, Fremont found some of the same stuff.Exploring the canyon of a small tributary of the Bear River in farsouthern Idaho on August 29 of that year, Fremont found "several curiouscaves" on the roofs of which he noticed "bituminousexudations from the rock" (Fremont 1845:141).
Sixteen years later, the U.S. Army Corps of Topographical Engineersassigned Captain James H. Simpson the task of discovering abetter wagon route across the Great Basin.... On July 16 Simpson wasexploring DomeCanyon in the HouseRange.... He found the"walls of the canyon full of small caves, and as usual showing a greatdeal of the resinous, pitchy substance that seemingly oozes outof the rock" (J.H. Simpson 1983:125). Unlike Manly's party, however,Simpson did not taste it; he guessed that it might have been"thedung of birds or small animals" (1983:125).
Simpson was very close to being right. These hard, shiny deposits thatare so often found cemented to the walls of caves and rockcrevices in the Great Basin are made by Neotoma.
What Manly and his friends ate, and what Simpson guessed may have hadsomething to do with the dung of small mammals, was partof a packrat midden.
Packrats also urinate and defecate on their middens. If the midden is
in the open, then the urine just washes away. But if the midden is in a sheltered spot—in a dry cave or crevice, for instance—theurine will crystallize and become about as hard as rock candy (recallManly's description).
This crystallized material is called amberat, referring to both itsconsistency and to its source. Because the urine saturates the midden,everything in the midden becomes encased in this hardened material. Aslong as the midden does not become wet, it can last for tensof thousands of years. As Goeffrey Spaulding and his colleagues have putit, many old, hardened packrat middens "resemble blocksof asphalt with the consistency and mass of an unfired adobe brick"(Spaulding et al. 1990:60). The oldest known middens are too oldto date by the radiocarbon method--that is, they are over 40,000 yearsold.