The discovery was in a cave East of the mountain range behind me. 

Our expedition was excavating the ruins of a prehistoric settlement on the valley floor. A site dated well over 250,000 years earlier. 

It was still early afternoon, but in just two days our expedition would have to pull out ahead of severe winter weather. 

Every morning and every evening for almost seven weeks, I stared at the thin trails. They were barely visible along the steep cliff wall rising high above the valley plateau.