Although there was no way at that time of accurately dating the layers, they did indicate the relative age of the deposits.
Reck disagreed, saying he had searched for tools and found none in 1913.
Reck found an early Iron Age site at Engaruka, where a stream from the Ngorongoro hills plunges down the western wall of the Gregory Rift at a point between Lake Natron and Lake Manyara, and published a description in 1913.
Also in 1913, Reck made an ascent of the 2,960 metres (9,710 ft) Ol Doinyo Lengai volcano in the Gregory Rift, about 15 kilometres (9.3 mi) south of Lake Natron He was the third geologist to do so.
He collaborated with Louis Leakey in a return expedition to the site in 1931.
Reck was born into a military family in Würzburg, Bavaria on 24 January 1886.