The formation of the Niagara River system of today which drains water from the upper Great Lakes into Lake Ontario was by no means a foregone conclusion. Rather, the selection of a location for the river was more like a close race or election about 12,000 years ago following the end of the last ice age.
There was once a very mighty waterfall, easily as impressive as Niagara Falls between what is now the Ontario town of Fonthill and St. Catharines. This St. Catharines Falls, as we will call it, has no large plunge pool that the falling water would have carved at it's base for a simple reason. When the falls was operational, the water fell into the former Lake Iroquois, the larger predecessor to Lake Ontario, which extended to the Niagara Escarpment.
The reason that a waterfall formed here is, of course, that this is the "breaking point" of the Niagara Escarpment, due to pressure from the Appalachian collision taking place across Pennsylvania between what is now Africa and what is now North America.
We know that when Niagara Falls began, the waters fell directly into the lake in a drop of about nine meters because the lake then extended to the escarpment at Lewiston-Queenston. By the time the lake shore withdrew to the present position, the flow of water over the St. Catharines Falls had drastically diminished. Even so, we can see the low area that the flow of water carved as it emptied into the retreating lake. It is Martindale Pond, which separates St. Catharines from Port Dalhousie.
The St. Catharines Falls was a circular cascade due to water flowing into it from south, east and, west. It lengthened as the flowing water established large channels, split in two as the flow of water diminished and finally, ceased altogether.
If we begin a tour of the falls where Pelham Rd. meets Effingham St. and go south on Effingham, we will climb the escarpment at Short Hills Provincial Park. On Effingham St., we see rolling ground carved by numerous channels of water approaching the falls from the west. There is a great dip east of Effingham St. that goes down to Sulphur Springs Dr.
Driving north down on Sulphur Spring Dr., we will see an inbound river from the west on Sulphur Springs Dr. after we pass Luffman Dr. If we head down Luffman Dr., we cross two wide former rivers before coming to a wide flat area. This was the ground between the two smaller falls into which the St. Catharines Falls split when the flow of water diminished.
There is another former river on Orchard Hill Rd., this was going to the other of the two branches of the St. Catharines Falls. The main falls split in two as the flow of water diminished to form a vague W-shape gap in the escarpment. Let's call the smaller western falls the "Pelham Falls" and the larger eastern falls the "Fonthill Falls".
Back on Sulphur Springs Dr. heading north again, we see two inbound rivers from the west before reaching Orchard Hill Rd. The channels that we earlier saw on Effingham St. have merged into rivers before reaching the falls.
Upon reaching Roland Rd. turn and head back down Sulphur Springs Dr., heading southward. There is a ravine across Sulphur Springs just in from Roland Rd., and another about 100 meters in.
By the side of Sulphur Springs Dr., I noticed a large, flat rock that was similar to the broken pieces of the top layer of dolostone visible in the Niagara Glen at Niagara Falls. The reason that Niagara Falls is a falls instead of a rapids is that the falling water eroded the softer layers below this hard top layer, which gradually broke off in pieces as it's underlying support eroded away. This proves beyond doubt that this was a falls like the Niagara.
Back heading south on Effingham Rd., we see a former river running toward the falls just east of the road. This river merged with one joining it at Kilman Rd. before heading down to Sulphur Springs Dr.
We reach the top of a steep hill at Tice Rd. and Moore Dr. Below the hill, we can clearly see the U-shape to the ground that is characteristic of land shaped by a glacier. The glacier had pressed up against this hill.
Turning left (east) on Route 20 toward Fonthill, we go over a wide valley in the road. This was formed by an extension of the glacier which thrust through a weak spot in the rock, probably formed by a riverbed in the previous inter-glacial era.
In the town of Fonthill, turn left (north) on Pelham St. You can see that Fonthill is where high ground begins, the ground to the east toward Niagara Falls is lower. There is a large incoming channel visible by Route 20 as you make the turn. Continuing down Hollow Rd., we are driving along the main channel to the falls, just as we were on Sulphur Spring Dr.
Another river at St. John's Rd. joins it. Two other rivers come in from the east at the beginning of Hollow Rd. When we reach McSherry Lane, we see at the end of the lane two rivers and a gully between them coming in. Back on Hollow Rd. opposite McSherry Ln., we see another incoming river. There are several large inbound channels and two inbound rivers. Hansler St. is built along the second of them. The main channel leaves Hollow Rd. at Orchard Hill Rd. Another river enters from the west south of Orchard Hill Rd.
This road is open only during warm weather and there are several vast former rivers along it which went to Fonthill Falls.
Back on Hollow Rd., we climb the hill and see that St. John's School is located on the east side of a former river. Holland Rd. is also alongside a former river amidst rolling ground carved by channels of water heading for the falls in this vast gathering place of water from the melting glacier.
There is the dip of a former river in Holland Rd. west of Cataract Rd. Many more dips in the roads can be seen in the area along Merrittville Highway, including the wide dip at Seburn Rd. The same thing along Cataract Rd. from DeCew Rd. to Seburn Rd.
It is easy to see that the DeCew Lakes in the area were once much larger. Such as the dip in the level of Merrittville Hwy. going south toward Lake Gibson. By a drop in Beaverdams Rd., we can see that Lake Gibson formed on lower ground above the escarpment.
In Thorold, we see a great valley on Ormond St. with the bottom at St. David's Rd. This was the route taken by water and followed the route of the Old Welland Canal. Let's call this the Thorold Falls, but it did not develop to the extent of the St. Catharines Falls before the water from the glacier ran out.
These falls were not the only ones to form in the area. There were smaller falls to the west of the St. Catharines Falls. Today, we can see the outlets that their waters carved along the shore of Lake Ontario as Fifteen and Sixteen Mile Ponds and Jordan Harbour. However, these smaller falls did not consolidate like the St. Catharines Falls because the flow of water from the melting glacier was not enough and it did not last long enough.
Below the escarpment around the St. Catharines Falls, there is a wide dip on Welland Ave. at Twelve Mile Creek. This was carved by the main flow of water from the St. Catharines Falls after the lake retreated. But by then, the flow of water over the falls was much diminished.
On 4th Ave., just east of 9th St., there is a large dip in the road. This was the main flow of water from what is now called the Rockaway Falls. This channel can also be seen above the escarpment before it reached the falls as a deep canyon on 8th Ave. at Wessel Dr.
The two dips on 4th Ave. just west of 9th St. were channels that can be seen above the escarpment as a channel on 8th Ave. at Staff Ave. and another just east of 17th St.
The large dip on 4th Ave. just east of 13th St. was the main flow into what is now Sixteen Mile Pond after the retreat of the lake. Above the escarpment, we see this as the deep channel on Staff Ave. just east of 17th St. The smaller dips on 4th Ave. on both sides of 15th St. are the same ones we see all around the intersection of 7th Ave. and 19th St. above the escarpment.
On King St. in the Village of Jordan, we see a great valley and a smaller one just past it. This was the flow of water that carved what is now Jordan Harbour and now houses Twenty Mile Creek, which goes over the escarpment as Ball's Falls. It shows up above the escarpment as the wide dip on Victoria Ave. south of Bethesda Rd. The wide dip on 7th Ave. west of 21st St. also went over this falls.
The reason, once again, for this extreme concentration of falls and channels in a limited area is that the high ground beginning at Fonthill and extending for several kilometers westward with Route 20 along it's apex acted as a wall that blocked the glacier and caused it's ice to pile up and to erode the numerous culverts and several falls in the ground when it melted.
CONCLUSION
The reason that the St. Catharines Falls is not the route of water today instead of Niagara Falls is clear. The ground it is on is too high and in any case, the permanent flow of water to it would be impeded by the high ground along Route 20. It is this high ground that begins at Fonthill and continues for several kilometers westward that created the St. Catharines and nearby smaller falls because it caused the ice of the last glacier to pile up and then carve the channels by force of flowing water when it melted.
The reason that the St. Catharines Falls was here is, once again, that this is the "breaking point" of the Niagara Escarpment, due to the pressure from the Appalachian collision that was taking place to the south.
There are many more channels above the escarpment than below because Lake Iroquois extended then to the escarpment and the channels below the escarpment were not carved by flowing water until the lake retreated to the shore of Lake Ontario today. When water in the area took the Welland River's preceding channel toward Chippawa, the falls was left virtually high and dry as it remains today.
This is not all of the close races that there was in the area to establish what the route of the water would be. If you drive across Grand Island on the American side from west to east along Whitehaven Rd., you will cross several former water routes formed after Lake Tonawanda began draining.
The two deep dips on the west of the island along the road, which form Six Mile Creek and Big Six Mile Creek were would-be routes that the Chippawa Channel might have taken when it formed but were a little too high to win out.
Aside from glacial impact craters. The thing that I want to add to our understanding of glaciers and their resulting landforms is the great erosive power of so much flowing water when the glacier melts. We know how glaciers shape the land and leave till and moraines behind. But I have yet to see a textbook discuss the great erosive power of the water itself from the melting glacier as it flows toward lower areas.
A glacier brings a virtual ocean of water to high ground where the water would not otherwise be. Ice covers about 10% of the world now but in the ice ages, it covered about 30%. The resulting flowing waters when the glacier melts can, I believe, account for so much of the world's landscape today.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment