Lake Monongahela
Last week I mentioned, in passing, an event that occurred very late in the life of the current drainage system in southwestern Pennsylvania – the development of Lake Monongahela – and glossed over its influence on the Chartiers Valley, while promising myself to discuss it in detail this week. This remarkable event occurred in recent (geologically speaking) time, yet long before the arrival of the human species. Scientists believe that the drainage system here one million years ago was strictly to the north, into a predecessor of the St. Lawrence River. An early version of the Monongahela River began in…








