Thursday, February 12, 2015

Fossil Bed on the Abiko Branch Line

EMU JR East 231 series travels near Kioroshi Station on the Abiko Branch Line

Along with trains, fossil collection is my lifelong hobby. For instance, I often visited fossil localities in the Tokyo metropolitan area, when I was a boy. Kioroshi in Chiba Prefecture was one of my favorite spots.

The Kioroshi Formation is young marine sediments, which were deposited about 125,000 years ago. At the time of the sedimentation, it was a warm climate and the sea level was higher than at present. Today, we can observe the densely-fossiliferous beds here and there in the Kioroshi Formation. The fossils are various kinds of bivalves, spiral shells and sand dollars... very beautiful.

In my boyhood, Kioroshi was just a small village. I could get fossils as much as I liked. It was a paradise for me, but today, Kioroshi has totally changed. Housing land development has been promoted to give residences for urban commuters. The fossil beds have been designated as a national natural treasure to preserve. As a matter of course, collecting fossils is strictly prohibited.

To visit this precious natural heritage, please take the JR East Abiko Branch Line and get off at Kioroshi Station. Connecting Abiko on the Joban Line and Narita on the Narita Line, there are 10 stations over the total operating length of 32.9 km. The track is a 1,067-mm-gauge single track and the electric system is 1,500 V DC overhead. Unlike my boyhood, modern commuter EMUs, the 231 series are operated every half an hour on the line. It takes just an hour from the downtown Tokyo area.

Fossiferous rock is seen near Kioroshi Station on the JR East Abiko Branch Line