in this video we're going to focus on interlocking Spurs and v-shaped valleys as River landforms in the upper course of the river the starting point of your River so if we first think about what type of exam questions we could be asked we could be asked about the formation of v-shape valley and interlocking Spurs how they're made we could be asked to label photographs annotate the photographs maybe even perhaps a diagram or we could be asked some type of OS map skill question so let's get stuck in with how the shape valleys and interlocking Spurs are formed so step one in the formation of a v-shape valley and interlocking Spurs is that in the upper course of our River we have a very low discharge we have a low volume of water in our River it is almost like a stream or a small trickle the river is surrounded on both sides by steep valley sides the river when it flows through these steep valley sides uses most of its energy to overcome friction with anything it comes into contact with whether it be on the riverbed or just moving through the valley what energy it then has left over is used by hydraulic action the sheer force of the water to deepen the channel by creating vertical downwards erosion the second stage in the formation of interlocking Spurs and v-shaped valleys is involving the geology of the upper course of the river being composed of hard rock or more resistant rock such as granite or slate freeze-thaw weathering takes place in this particular part of the long profile of the river and this is where water gets into cracks between the rocks and freezes at night expanding those cracks and then thawing or melting during the day over time what happens through this process is that the river channel becomes wider giving the valley a steeped v-shaped cross profile over time this process continues to weaken the rock in the upper course of the river valley which breaks the small material and that material then shifts down the valley sides into the river the river then transports this material further downstream and finally the last step in the formation of this landscape involves the actual path taken by the river winding between the interlocking Spurs or the valley sides of the upper course of the river due to the obstacles of hard rock or more resistant rock in its path the river decides to take the easiest route it possibly can over the land this results in land interlocking or crossing over each other as you can see in this diagram on the screen this is known as an interlocking spur and to visually see what this land form looks like on photographs which examiner's could provide for you to label as you can see on the screen that I am doing now we have interlocking Spurs on this photograph showing those steep valley sides I know it's an interlocking spur because I can see each valley side Criss crossing past one another as I've indicated on these lines you can see on the screen and then a different alternative is an image where you can actually see the river running through the valley and these interlocking Spurs again and what's so special about this particular photograph is that you can actually see the river carving out the landscape and creating that v-shaped valley cross profile alternatively you could also be given some type of OS map question where you might be asked to identify the upper course of a river or where we potentially would find evidence of interlocking Spurs and v-shaped valleys and for this particular style of question you would need to concern yourself with the contour lines these brown light-colored lines with numbers associated with them on the line which show us the metres of sea-level in terms of the land what you can see that I'm doing on the screen here is I'm actually drawing over them to make them a little bit more obvious for you to see these contour lines and what I can see is that the river flows between my lines that I'm drawing on the screen and all of these lines are very closely packed together the closer they get to my River and that indicates steep valley sides so this potentially could then suggest a presence of interlocking spurs or v-shaped valleys