On a July morning in 1911, while strolling up the Ayahuaycco quebrada, an affluent of the Chunchullumayo, in company with Professor Foote and Surgeon Erving, my interest was aroused by the sight of several bones and potsherds exposed by recent erosion in the stratified gravel banks of the little gulch.  Further examination showed that recent erosion had also cut through an ancient ash heap.  On the side toward Cuzco I discovered a section of stone wall, built of roughly finished stones more or less carefully fitted together, which at first sight appeared to have been built to prevent further washing away of that side of the gulch.  Yet above the wall and flush with its surface the bank appeared to consist of stratified gravel, indicating that the wall antedated the gravel deposits.  Fifty feet farther up the quebrada another portion of wall appeared under the gravel bank.  On top of the bank was a cultivated field!  Half an hour’s digging in the compact gravel showed that there was more wall underneath the field.  Later investigation by Dr. Bowman showed that the wall was about three feet thick and nine feet in height, carefully faced on both sides with roughly cut stone and filled in with rubble, a type of stonework not uncommon in the foundations of some of the older buildings in the western part of the city of Cuzco.

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Figure

Huatanay Vallye, Cuzco, and the Ayahuaycco Quebrada
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Even at first sight it was obvious that this wall, built by man, was completely covered to a depth of six or eight feet by a compact water-laid gravel bank.  This was sufficiently difficult to understand, yet a few days later, while endeavoring to solve the puzzle, I found something even more exciting.  Half a mile farther up the gulch, the road, newly cut, ran close to the compact, perpendicular gravel bank.  About five feet above the road I saw what looked like one of the small rocks which are freely interspersed throughout the gravels here.  Closer examination showed it to be the end of a human femur.  Apparently it formed an integral part of the gravel bank, which rose almost perpendicularly for seventy or eighty feet above it.  Impressed by the possibilities in case it should turn out to be true that here, in the heart of Inca Land, a human bone had been buried under seventy-five feet of gravel, I refrained from disturbing it until I could get Dr. Bowman and Professor Foote, the geologist and the naturalist of the 1911 Expedition, to come with me to the Ayahuaycco quebrada.  We excavated the femur and found behind it fragments of a number of other bones.  They were excessively fragile.  The femur was unable to support more than four inches of its own weight and broke off after the gravel had been partly removed.  Although the gravel itself was somewhat damp the bones were dry and powdery, ashy gray in color.  The bones were carried to the Hotel Central, where they were carefully photographed, soaked in melted vaseline, packed in cotton batting, and eventually brought to New Haven.  Here they were examined by Dr. George F. Eaton, Curator of Osteology in the Peabody Museum.  In the meantime Dr. Bowman had become convinced that the compact gravels of Ayahuaycco were of glacial origin.