Brockhaus and Efron Encyclopedic Dictionary
The 1906 Russian "Brockhaus and Efron Encyclopedic Dictionary" writes that Olonka flows from Lake Topornoye, through lakes Vagvozero, Utozero and Torosozero, and eventually to Lake Ladoga. This section is now referred to as Topornaya (Топорная). The highest point of this drainage chain is Kaskozero, which overspills into Lake Pyyre Järvi (Pyureyarvi, Пюреярви), which is connected by a shallow creek to Topornoye.