Observations: April 28, 1998 Time: 2:45 pm Weather: Sunny & Cool

Fire & Ice Looking up at the rock face on the west end of Saints Rest Beach is like looking into a history text. A close examination will tell you of the events that shaped the park back as far as 300 million years ago. The dark grey rock is volcanic in origin. In fact, the entire peninsula is an ancient volcano. Lava (liquid rock) flowed out of cracks in the Earth from a depth of 40-50 km and cooled into a mineral called basalt. Vertical band of siltstone in basalt rock face at Saints Rest Beach Look for the vertical band of red layered rock. It is not volcanic, but mud from an ancient sea floor. At the time of eruption this area was under water. The lava flowed over and under the cold, red mud and solidified. Later geological activity then moved this layer (called siltstone) to the upright position it is now.

See the horizontal scratches in the rock face. These were made by glaciers moving across the rocks during the last ice age. Glaciers are huge layers of ice (up to 1.5 km thick) and were formed approximately 2 million years ago. The scratches were caused by the weight of the ice pushing down on debris (rocks, etc.) embedded in the moving ice. One square metre of ice at this thickness (1.5 km) would weigh approximately 1.5 million kilograms, or the weight of about 850 pickup trucks!

Glacial Remains To the right of the rock face you will find an eroding bank of mud, rocks and soil. The rocks and soil were stuck in the ice when the last glacier melted about 13,000 years ago. Similar layers of glacial debris called "till" are found along the park's shoreline banks. These mounds of till formed a large continous barrier wall (berm) across the west side of the city. It blocked the pre-glacial St. John River from flowing over and around the park (see figure 1). It forced the river to find a route through Reversing Falls (see figure 2) rather than flowing out into the bay through the saltmarsh.   Figure 1, Pre-Glacial outlet of the St. John River Figure 2, St. John River today

The Naturalist's Notebook is a regular publication. If you have any questions or topics that you would like to see addressed, please call John Gilbert, Manager, Fish and Wildlife, J.D. Irving, Limited, (506) 632-7777.