Scientists: Oldest stone tools found in Kenya

(CNN)Archaeologists have made a discovery that may mean our school textbooks have to be rewritten.

According to a paper published by the science journal Nature, the oldest stone tools made by our human ancestors have been discovered in northwestern Kenya and they date back 3.3 million years -- about 700,000 years before the oldest tools previously unearthed.

"We have extended the archaeological record by almost a third," Jason Lewis, the co-author of the paper, told CNN. "That's like finding cell phones back in the early 1900s."

Previous evidence found in Ethiopia suggested that the oldest stone tools of the genus Homo, to which modern-day humans belong, dated back 2.6 million years.

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