In the extract which follows, taken from a collection of scientific essays, the writer describes a discovery made during an archaeological dig. 'Let's go back this way and survey the bottom of that gully over there.' The gully in question was just over the crest of the rise where we had been working all morning. It had been thoroughly checked out at least twice before by other workers, who had found nothing interesting. Nevertheless, conscious of the 'lucky' feeling that had been with me since I woke, I decided to make that small final detour. There was virtually no bone in the gully. But as we turned to leave, I noticed something lying on the ground partway up the slope. ‘That's a bit of a hominid¹ arm,' I said. 'Can't be. It's too small. Has to be a monkey of some kind.' We knelt to examine it. 'Much too small,' said Gray again. I shook my head. 'Hominid.' 'What makes you so sure?' he said. 'That piece right next to your hand. That's hominid too.' 'Good grief!' said Gray. He picked it up. It was the back of a small skull. A few feet away was part of a femur: a thighbone. We stood up, and began to see other bits of bone on the slope: a couple of vertebrae, part of a pelvis-all of them hominid. An unbelievable, impermissible thought flickered through my mind. Suppose all these fitted together? Could they be parts of a single, extremely primitive skeleton? No such skeleton had ever been found-anywhere. 'Look at that', said Gray. 'Ribs.' A single individual. 'I can't believe it,' I said. 'I just can't believe it.' 'You'd better believe it!' shouted Gray. ‘Here it is, Right here!' His voice went up into a howl. I joined him. In that 110-degree heat we began jumping up and down. With nobody to share our feelings, we hugged each other, sweaty and smelly, howling and hugging in the heat-shimmering gravel, the small brown remains of what now seemed almost certain to be parts of a single hominid skeleton lying all around us. 'We've got to stop jumping around,' I finally said. 'We may step on something. Also, we've got to make sure.' 'Aren't you sure, for heaven's sake?' 'I mean, suppose we find two left legs. There may be several individuals here, all mixed up. Let's play it cool until we can come back and make absolutely sure that it all fits together.' We collected a couple of pieces of jaw, marked the spot exactly and got into the blistering Land-Rover for the run back to camp. On the way we picked up two expedition geologists who were loaded down with rock samples they had been gathering. 'Something big,' Gray kept saying to them. ‘Something big. Something big.' That afternoon everyone in camp was at the gully, sectioning off the site and preparing for a massive collecting job that ultimately took three weeks. When it was done, we had recovered several hundred pieces of bone (many of them fragments) representing about forty percent of the skeleton of a single individual. Tom's and my original hunch had been right. There was no bone duplication. But a single individual of what? On preliminary examination it was very hard to say, for nothing quite like it had ever been discovered. The camp was rocking with excitement. That first night we never went to bed at all. ¹hominid: the group consisting of all Modern and Great Apes, including humans