exploration: The Americas river began in northwest Africa and published his proof, tracing its course across northern Africa, while admitting that it ran underground for some distance Bizarre as this theory seems, it was still accepted in the 19th century Around 60 c.e Roman officers moved up the Nile for a planned invasion of Ethiopia by the emperor Nero (r 54–68 c.e.), reaching the marshes in present-day southern Sudan and hearing reports of the lakes beyond A traveler named Diogenes, perhaps a generation later, moved inland from the vicinity of Zanzibar and saw or heard about the high mountains of central Africa, providing the name Mountains of the Moon, and he was also aware of the lakes around the source of the Nile But the actual source itself remained elusive until the 19th century, and there was no further exploration of Africa in classical antiquity Roman trade items and coins reached the southern parts, but the Romans seemed unaware of the interior south of a line from Zanzibar to Cameroon To the east the journey of Alexander the Great (356–323 b.c.e.) had brought India, and the routes to it, into Mediterranean knowledge, though details such as the size and shape of the Arabian Peninsula continued to be refi ned in the Roman period In the first century c.e Sri Lanka, known since the fourth century b.c.e., was examined in detail, and a Roman trading post was established at Arikamedu on the east coast of India around 50 c.e In the following century the Bay of Bengal was explored by a certain Alexander, who may have gone as far as the Cambodian coast; by late in the century a Roman trading post may have existed at Oc-èo in the Mekong Delta China had been known since Greek times as the origin of silk; the name of the region first appears in Greek accounts (as “Thina”) of around 50 c.e There is no evidence that Mediterranean peoples actually reached China until around 100 c.e The one definitive record of Roman contact with China is in 166 c.e., when an embassy from the emperor Marcus Aurelius Antoninus (r 161–180 c.e.) reached China and was recorded in Chinese records as a mission from An-Tun From that time there were sporadic contacts and frequent trade in both directions Through trade routes the Romans were aware of parts of central Asia east of the Caspian Sea, though little was added to the knowledge existing since the late fourth century b.c.e Routes north from the Black Sea to the Baltic region had also long been known, but otherwise Siberia lay completely outside ancient knowledge Japan and southeastern Asia were similarly unknown to the Mediterranean world Existence of the Western Hemisphere had long been presumed, largely on the basis of geographical symmetry, and much fantasy literature was written about the existence of a western continent This was an inspiration to the European explorers of the Renaissance, but there is no evidence of European contact with the New World until Viking times, although the mid-Atlantic islands such as the Azores and Madeiras had been known since their Carthaginian discovery 445 THE AMERICAS BY J J GEORGE At a site in Midland, Texas, the skull of a woman lacking facial bones was found protruding from sand in a windblown depression Snail shells found in a layer of earth below her yielded a carbon 14 date of about 11,000 b.c.e Artifacts found with her resembled Folsom-style objects and were dated to about 8000 b.c.e Folsom, along with Clovis, are two of the earliest American cultural patterns Scientists have suggested that the woman probably died there between 9000 and 10,000 b.c.e In central Mexico at a place called Tepexpán the skeleton of a man was found in late Pleistocene sediment and dated 9000–8000 b.c.e., but the excavation was poorly reported Chemical tests nonetheless confirmed the date In the 1930s the archaeologist Junius Bird excavated a few skeletons from a South American site called Palli Aike in Patagonia Bird discovered sloth and horse bones in an overlying deposit and a fishtail point deposit in an underlying lava deposit Carbon 14 dates for these items ranged between 9000 b.c.e and 8700 b.c.e Are these the remains of some of America’s early explorers? Ultimately, the idea of exploration in the ancient Americas presents a peculiar conundrum On the one hand, the period’s defining quality is exploration, when one considers exploration’s relation to migration As new peoples arrived in the Americas and diff used south, eventually reaching the southern tip of South America, their very existence was a form of exploration On the other hand, the idea of exploration in a more familiar form, such as the maritime expeditions of Captain James Cook, Ferdinand Magellan, and Christopher Columbus or the overland exploration of the western United States by Meriwether Lewis and William Clark, in the name of colonization or science or Manifest Destiny, was virtually unknown until much later Exploration is a defining aspect of American migration and settlement and has its beginnings at Beringia, the name assigned by geologists for the continuous landmass that once connected Siberia and Alaska and offered a broad highway to the Americas not only to early humans but also to the animals they hunted The traditional theory says the first North Americans were big game hunters on foot, following large animals such as the extinct mammoth During the last glacial episode (10,500–11,000 years ago), when much of the earth’s water was locked up in frozen glaciers and water levels worldwide were much lower, the landmass was as much as 1,000 miles wide The present geographic proximity of Alaska and Siberia is itself suggestive of an easily overcome barrier; only 56 miles of water separates the two landmasses In the winter the strait often freezes and it is possible to walk across the ice It is generally agreed that the diff usion of the earliest peoples crossed into the Americas via this passage Once in Alaska, however, the early explorers would have encountered a nearly impenetrable barrier to southward progress—the same glacial advances that lowered sea levels and revealed Beringia also covered Canada and northern