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Ancient fossils found in eastern Japan rocks left exposed by typhoon

This photo provided by Fumio Takahashi shows the Kaneharanishiki scallop fossils found on Mount Minami in the Kanagawa Prefecture city of Sagamihara.

SAGAMIHARA, Kanagawa -- Five fossils of a type of scallop that is said to have lived in cold seabed waters millions of years ago have been found in rocks left exposed here in the wake of October 2019's Typhoon Hagibis.

The five "Kaneharanishiki" scallop fossils were found by 67-year-old Fumio Takahashi, who worked for the Tsukui town government in Kanagawa Prefecture in eastern Japan before the town was amalgamated. The fossils were in a geological stratum known as the Nakatsukyo Formation of the Aikawa Group in the prefecture, said to have been formed 5.6 million to 8.6 million years ago when the Tanzawa mountain range centered in northwestern Kanagawa Prefecture was beneath the sea.

After Typhoon Hagibis, the 19th typhoon of 2019, tore through Japan in October, an approximately 320-meter stretch of the so-called Tonan Rindo (south-east forest road) on the 544-meter-high Mount Minami in the prefectural city of Sagamihara was washed away. The fossils were found when the exposed rock was examined this year.

Photos of the specimens and a map of where they were found were sent to Kiminori Taguchi, a curator at Kanagawa Prefectural Museum of Natural History with paleontological expertise, who confirmed that they were Kaneharanishiki fossils.

Kaneharanishiki refers to a type of scallop said to have inhabited cold waters some 12 million years ago. When the Tanzawa mountain range was in the sea, the area is thought to have been the southern limit of frigid water that flowed into the area from the north.

Previously such fossils have been found in large numbers along the Kanno River, which branches off the Doshi River, as well as in the Kanagawa Prefecture municipalities of Atsugi, Aikawa and Kiyokawa, and the former town of Tsukui, which was amalgamated into the city of Sagamihara. However, Takahashi says it is the first time they have been found along the forest road.

(Japanese original by Kazuo Takahashi, Sagamihara Local Bureau)

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