The Niagara Valley

The most important reason that Niagara Falls exists as it does today is, of course, the escarpment. The water in the vast upper Great Lakes watershed will inevitably find it's way to Lake Ontario and at some point must fall over the escarpment.

THE NIAGARA VALLEY

I have found what must be the next most important factor in the formation of Niagara Falls after the escarpment. I have named it the Niagara Valley. It is a wide valley in the underlying rock layers aligned roughly north-south. This valley is very old and is not easily visible today since it has been largely filled in by the Niagara Falls Moraine, the high ground on the Canadian side by the falls, and carved up by the Niagara River.

But this valley was the underlying factor in all that happened at Niagara Falls. This posting may actually be considered as the most important one about Niagara natural history because all of the other Niagara postings are about the effects of flowing water and moving glacial ice, but this one is about the underlying geology which shapes all else.

Here is the map link that I usually use. The straight-line section of the Lower Niagara River from the ninety degree angle at the falls north northeastward to where Bridge Street on the Canadian side and the Whirlpool Bridge is located runs along the low line of the Niagara Valley, which extends westward into Canada and eastward into the U.S.: www.maps.google.com .

The place that this old valley is most visible today is on Thorold Stone Rd. in Niagara Falls, Canada. If you go eastward, toward the river, on that road from the intersection with Dorchester Rd., you will reach a high point and then begin a long and gradual drop that reaches all the way down to the present Niagara Gorge. This is the western side of the valley.

A few miles to the southeast, on the American side, anywhere near the falls the southwestward slope of the rock strata is unmistakable. From the intersection of John B. Daly Blvd. and Rainbow Blvd., if you look westward along Rainbow Blvd. toward the falls, you will see another long and gradual drop, this time in the opposite direction. This is the eastern side of the valley. This valley was not carved by water at all but is along the underlying rock strata.

Another glimpse of the western side of the valley can be seen in the way that Lundy's Lane climbs higher west of the intersection with Portage Rd. in Niagara Falls, Canada. Although here, the valley has been covered by the Niagara Falls Moraine, which was deposited by a later glacier.

The upper rapids above the falls begin at the eastern edge of the slope of the Niagara Valley in the Niagara River. We know that these rapids are created by the same slope in the underlying rock that we see along Rainbow Blvd.

A large amount of soil and loose rock was deposited in the valley by an ice age glacier. This is what we now refer to as the Niagara Falls Moraine, and is seen as the high ground on the Canadian side of the falls, including the slope of Clifton Hill. The eastward part of the moraine was pushed in to it's present position by the falls by sliding fragments of the last glacier as it melted and broke apart. This moraine, and the Niagara River that made a northward turn when it collided with it, are the reasons that the valley is so difficult to discern today.

FORMATION OF THE NIAGARA VALLEY

To understand how the Niagara Valley, and thus the falls as they are today, formed we must look at the big picture of North America. The Appalachian system of mountains in the eastern USA was formed by the collision between what is now Africa and what is now North America, as described in the posting on the geology blog "All About The Appalachians". This long system includes the Allegheny, Blue Ridge, Catskill, Adirondack, Green and, White Mountains. It also includes the system of ridges in Tennessee and Kentucky that parallels it.

The Appalachians are much older than the Rockies in the western part of the continent so the collision that formed them happened long before the collision of the entire western hemisphere with the Pacific Plate. The collision that formed the Appalachians also forced up layers of rock strata adjacent to the mountains such as the Allegheny Plateau in New York and Pennsylvania.

Now, back to Niagara Falls and the underlying Niagara Valley. This valley includes the slant in the underlying rock strata to the southwest above the falls at about 20 feet (6 meters) per mile (1.5 km). This is what gives us the upper rapids and is why the water above the falls is deeper on the Canadian side.

The underlying Niagara Valley is most obvious here in it's contrast with the opposite slope of Thorold Stone Road. The southward element of the slope in the underlying rock above the falls is not a part of the Niagara Valley. The southward slope is a property of the escarpment itself and is visible in the numbered streets in the LaSalle section of Niagara Falls if we look south from Niagara Falls Blvd. along the 70s numbered streets. This direct southward slope, with no westward slope element, means that the 70s streets, in Niagara Falls NY, are located eastward beyond the Niagara Valley.

The fracturing of the rock strata, as the pressure of the Appalachian collision met the Niagara Escarpment, was not perfectly neat. The resulting southwestward  slope, the southward element of the slope is the result of the sawtooth shape of the escarpment and the westward element is the result of the Niagara Valley, is greatest near the falls, on the American side. But lesser westward slopes, the result of the Appalachian collision forming the Niagara Valley, can be seen well to the east in the landscape of Niagara Falls, NY.

There is actually a subtle boundary region where the primary underlying slope becomes southwestward instead of southward. If we look east on John Ave. from 66th St., we can see in the surface of the street the beginning of the westward slope that extends down to the falls. The subtle westward slope can also be seen in the parking lot of Home Depot on Builder's Way. The westward slope of Girard Avenue, between the Interstate 190 and 56th Street, is just barely perceptible. Closer in the direction of the falls, if we look westward along Pine Avenue from Hyde Park Boulevard, the westward slope becomes somewhat more perceptible. On Main Street, near the area of the falls, the westward slope of the Niagara Valley is very definite. Further north, the westward slope of Ontario Avenue is another place where we see the Niagara Valley.

The point of this is that this section of the lower Niagara River, below the falls, is aligned from south southwest to north northeast along exactly the same angle as are the Appalachian Mountains and ridges before the great curve of the collision front across Pennsylvania. Remember that this section of the river flows along the low line of the Niagara Valley. This can be easily seen if we look at a map of eastern North America alongside a map of Niagara Falls.

Thus, it is my conclusion that the continental collision which resulted in the Appalachian Mountains exerted tremendous force that caused a fracture in the rock strata at a distance and resulted in the formation of the Niagara Valley.

The Niagara Escarpment broke in two places , one on each side of it. The most clear break is the one on the side of the escarpment away from the collision front, at Short Hills Provincial Park near St. Catharines. On the opposite side of the escarpment is the break which forms the Niagara Valley. This break caused a shift in the terrain at right angles to the break at the Niagara Valley, which is why the Upper Niagara River shore of the city of Niagara Falls, NY forms a continuous line with the axis of the Decew Lakes near St. Catharines and the "breaking point" of the escarpment on it's opposite side. This is also why the Upper and Lower Niagara Rivers, above and below the falls, seems to form a perfect right angle. This should not seem unusual at all as the Niagara Region is really not far from the Allegheny Plateau that was created by the collision.

The river from the Horseshoe Falls to the Whirlpool Bridge represents the low point of the Niagara Valley. Water always seeks the lowest point and this is why this stretch of the lower river follows the course it does today. To get to the falls, water in the upper rapids is flowing down the east side of the Niagara Valley. Once the river passes the Whirlpool Bridge, it is past the end of the valley and it's course diverges.

THE HUMBER LINE AND THE NIAGARA VALLEY

Let's now turn to the place where the straight line section of the lower Niagara River curves to the west, along what is known as the Lower Niagara Rapids, toward the whirlpool in the Niagara River.

Remember in "All About The Appalachians", we saw how the geographical features created by this tectonic collision revolve around what I defined as the Humber Line, named for the valley across Toronto where it is most visible. The Humber Line is the line that I noticed extends from the "focal point" of the curve of the Appalachians, around the city of Harrisburg in Pennsylvania, through the long axis of the elongated Georgian Bay in Ontario. In the opposite direction from Harrisburg the Susquehanna River, which meanders around northeastern Pennsylvania before reaching Harrisburg, suddenly adheres to a straight line flow along the Humber Line after passing Harrisburg.

If we follow the line of the Humber Line through the general area of the Niagara River, we see that it forms the straight line of the easternmost shore of Lake Erie, from Blasdell to downtown Buffalo. We then see that the Humber Line forms the straight line of the southwestern shore of Navy Island, the uninhabited Canadian island in the upper Niagara River. Notice that this shoreline is a perfect continuation of the easternmost shore of Lake Erie.

We then see that the Humber Line intersects the Niagara Valley. In fact, the Niagara Valley ends at the Humber Line, where the lower Niagara River ceases to be a straight line and curves along the lower rapids. The Humber Line then appears along the northern shore of Lake Ontario at Humber Bay, in Toronto. The well-known drop in elevation along east-west streets to the west of downtown Toronto, such as Bloor Street, represents how the land is elevated on the east side of the Humber Line due to the difference in pressure as the collision front of the Appalachians shifted direction across Pennsylvania.

(Note-I don't want to digress too much here, but the reason that this shift caused by the change in direction of the Appalachian collision front is so well-defined along this line is that the Humber Line was actually once a longitudinal line of magma emergence when the north pole was migrating across Canada, from it's former position at what is now the Great Basin of the western U.S. to it's present position, as described in "The Story of Planet Earth" on the geology blog).

The reason that the Niagara Valley ends at the Humber Line, at the beginning of the Lower Rapids, is that the break in the structure of the Niagara Escarpment which formed the Niagara Valley only took place to the west of the Humber Line. To the west of the Humber Line, the pressure on the land from the south increased as the collision front of the Appalachians changed direction as it continued eastward. To the east of the Humber Line, the force was enough to simply shift the Niagara Escarpment to the north.

This meant that there were fewer special effects on the land, such as this Niagara Valley, than there were to the east of the Humber Line. To the west of the Humber Line, there was not quite enough force to shift the entire escarpment so the force went into creating various special effects. The shifting of the escarpment itself created a special effect, that can easily be seen on a map, as the smooth bulge of land extending out into Lake Ontario between the cities of St. Catharines and Rochester, as we saw in the posting "The Niagara Escarpment Bulge And The Appalachian Collision".

Another such "special effect" of the pressure against the Niagara Escarpment west of the Humber Line is the rocky ridge which extends to the west of the town of Fonthill, Ontario, and which was described in "All About The Appalachians" on the geology blog, in the section "The Appalachian Collision And The Niagara Escarpment". Just as the Niagara Valley only continues until it meets the Humber Line, this rocky ridge only continues eastward until it meets the "breaking point" of the escarpment, which is at Short Hills Provincial Park, near St. Catharines. The Break in the escarpment, caused by building pressure along the Appalachian collision front to the south, should logically have taken place right at the Humber Line. The reason that it didn't is that the rock strata has a structure of it's own and is not "fluid". So, the break in the escarpment took place just west of the Humber Line, at Short Hills.

There have been two rivers across the Niagara area, from Lake Erie to Ontario, the present Niagara River and the St. David's River in the warm period before the last ice age. The St. David's River flowed from what is now Dufferin Islands, on the Canadian shore of the Niagara River, across what is now Goat Island. The sections that are common to both rivers are the lower rapids and the whirlpool.

The St. David's River flowed through what is now the whirlpool and met the escarpment at the Ontario village of St. David's, hence it's name. Along the QEW Highway (Queen Elizabeth Way), west of Stanley Avenue, there is a wide area of a lower elevation adjacent to the village of St. David's which is a remnant of this former river before it was mostly filled in by soil and loose rock carried along by the glaciers of the last ice age.

But notice that this St. David's River followed the Humber Line exactly from the point where it encountered the line in what is now downtown Niagara Falls, NY. The St. David's River route from the whirlpool at the village of St. David's is right along the Humber Line. The St. David's River followed the Humber Line, the lower Niagara River follows the Niagara Valley which ends at the Humber Line. The whirlpool formed when the Niagara River's flow and falls excavated the loose fill of the former St. David's River, and this directed the Niagara River in another direction so that it does not follow the course of the Humber Line.

RIDGES WITHIN THE NIAGARA VALLEY

One other notable feature of the area is the so-called Lyell-Johnson Ridge. This is a low, rounded ridge that cuts directly across the valley. When the falls, eroding it's way southward, about 3,500 years ago cut through the high ground at Hubbard's Point, Lake Tonawanda began to drain and Niagara Falls as we know it began to take shape.

This ridge is visible along River Rd. in Niagara Falls, Canada extending south from the Whirlpool Bridge with the high point at Eastwood Cr. It is also visible on the American side on Whirlpool St., as you pass Spruce and Cedar Aves.

Another such ridge can be seen in Niagara Falls, Canada on Stanley Ave. If you head south from Bridge St., you will go over the same type of low and rounded ridge.

These two ridges are part of the rock structure, and are not glacial in origin. They can in no way be explained in terms of the Niagara River. But, if we consider the Humber Line, it is easy to see that both ridges are immediately west of it and, like the Niagara Valley which they are within, terminate before the Humber Line. There are no such ridges to the east of the Humber Line. These two ridges are explained as a part of this scenario with the Appalachian collision. They are reeves in the rock strata that were formed by the same pressures as the Niagara Valley, and are congruent to the rocky ridge west of Fonthill.

(Note-this Lyell-Johnson Ridge also helps explain why the embayment at Dufferin Islands, that I have discussed in other Niagara postings such as "Dufferin Islands And The Former St. David's River", is where it is. The embayment is a former whirlpool from the previous warm inter-glacial period. It is located as far west as it can be due to the underlying slope of the rock strata along the eastern side of the Niagara Valley but it could not be any further west or else it would be too low for water from it to be able to cross the Lyell-Johnson Ridge on it's way northward to the escarpment).

One other such ridge, which is within the Niagara Valley and formed by the same pressure from the Appalachian collision as it, is what some natural historians refer to as "Niagara Island". This is not an actual island but is an area of a little higher elevation in the rock strata right downtown in Niagara Falls, NY near the falls. The large hotel with a curved front brick facade, John's Hotel Niagara, is built on this elevation. The reason for referring to it as an island is that it was briefly an island when the former Lake Tonawanda drained after the falls, cutting it's way backward to it's present location, cut through the Lyell-Johnson Ridge about 3500 years ago.