There are many interesting types of rocks along the Rideau including this conglomerate located at Rocky Narrows, on the east shore of Big Rideau Lake. While it looks like a very coarse type of cement, it is a natural feature, formed several hundred million years ago.
Conglomerates form in spots where water action puts unsorted stones of varying sizes (riverbeds, shorelines, alluvial fans, etc.) and fills the spaces between them finer material. Once buried, these get cemented by heat and pressure to form rock. The age of this particular conglomerate is uncertain. It sits above Precambrian rocks in this area that were formed a billion years ago, but under Paleozoic rocks which were formed 500 million years ago. Bottom line is that this conglomerate unit is very old.
|
Photo Gallery 
