Hart's tongue in the hollow way

I was checking out ferns this afternoon in a steep wood which has a spectacular hollow way, or sunken track, running through it. The banks of the hollow way, which are up to 10-12 metres in places, were covered in a variety of ferns. The Hart's tongue, Asplenium scolopendrium, was particularly plentiful given the chalky soil. The hollow ways cutting through these woods are ancient trackways that have been cut lower and lower into the chalk by erosion over hundreds of years due to horse traffic and water flow in winter. In this area horses would pull timber from the woods down into the vale and drag carts full of chalk or lime up to the acid grassland on top of the hills, where it would be used to 'sweeten' the fields and make them more productive. At the moment this track, the county boundary between Hertfordshire and Buckinghamshire, is so wet and muddy it is almost impassable, but in the summer it will be baked hard.