Webster’sWebster’s FallsFalls --VirtualVirtual FieldField TripTrip--

School of GEOGRAPHY & GEOLOGY

Prepared by Zachary Windus Carolyn Eyles & Susan Vajoczki and Liz Kenny From McMaster University follow into Dundas. Cootes Drive becomes King Street (Regional Road 8) up the to Greensville. Turn right at Harvest Road and travel approximately 2 km to Short Road. Turn right on Short Road and follow it to Fallsview Road where there is a parking lot for the Webster’s Falls Conservation Area on the right hand side of the road. Webster’sWebster’s FallsFalls High Flow

Low Flow

Features at this site…

• In the upper part of the conservation area the channelized creek can be observed and the old flood plain is clearly defined.

• The upper geological units of the Niagara Escarpment are exposed (Lockport Fm down through the Fm).

• The Grimsby Fm can be observed at the very base of the falls. (This location is not recommended for sedimentary logging exercises due to frequent rock falls)

• and undercutting of the less resistant shale is clearly visible behind the waterfall.

• Tufa deposits can be observed 10m SW of the falls where water seeps from fractures in the Lockport dolostones.

• A well maintained trail allows for investigation of the natural creek downstream of the falls. Spencer Creek has been channelized at the top of the falls. The old flood plain of the Spencer Creek is clearly defined in the park area. The channelized creek flows over the Niagara Escarpment. Schematic Section of Webster’s Falls

Highlighted formations are visible at this site. GEOLOGICAL UNITS EXPOSED AT WEBSTER’S FALLS

Lockport Fm

Rochester Fm

Irondequoit Fm

talus Reynales Fm Thorold Fm Grimsby Fm Reynales, Thorold, and Grimsby Fms are mostly covered by talus at this location, but are exposed further downstream. Ancaster Member

Gasport Member

LockportLockport FormationFormation RochesterRochester FormationFormation

Lockport Fm

Rochester Fm

1.5-2m Irondequoit Fm

Reynales Fm IrondequoitIrondequoit FormationFormation

Fallen piece of the Irondequoit Fm containing vugs. TopTop ofof thethe FallsFalls

at low flow

and high flow

Top of Falls Large, angular dolomite blocks from the Lockport and Irondequoit formations accumulate at the base of the falls. Undercutting of the dolostone units occurs as the shales of the Thorold and Grimsby Formations are eroded away. DownstreamDownstream ofof thethe Falls…Falls…

Low Flow Falls

High Flow Talus Red-brown stained tufa deposits (calcium carbonate precipitates) can be observed where water seeps from fractures in the Lockport Formation. Little Webster’s Falls Acknowledgements:Acknowledgements:

Map Source Data: DMTI Spatial Inc.

Photographs by Ben Cowie, Luisa DaSilva, Liz Kenny, and Zachary Windus

Based on earlier slide field trip prepared by Alvin Chan and Sandra Rolph