1 Black Hill car park
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Cat’s Back Voyage is intended to help you understand the landscape of this beautiful area by providing you with information and images as you climb from Black Hill car park towards Black Hill.

However, it also allows you to test your observation skills (and a bit of general knowledge) by answering questions and will give you a score at the end.

The app includes reconstructions of the probable environment of this place at various times in the past, the reconstructions are available by touching ‘then’ (in the app, but in this web version they are from the links on the map page). Where you will find ‘palaeo views’ in different directions. Information on animals and plants of the time and even a possible weather forecast.

Touching the clock (in the app) will give you additional information on a global setting for different times throughout the 4600 million years of the Earth’s existence.


Black Hill car park

Black Hill car park, the start of the Cat’s Back Voyage and Task Site 1 where you can complete the introductory task before setting off.

The app should have a green light flashing on the ‘do it’ button. This means you are in an area where a task may be answered.

Task sites 2, 3, 4 and 5 can only be answered when you are in those Task areas, as indicated by the green flashing indicator on the ‘do it’ button.

If you wish to answer the questions and build a score, then be on the look out for Task sites!
In the app you do get audio alerts when you enter task site areas, so long of course as audio on your phone/tablet has not been muted or set to low to hear.


Olchon Valley

The interesting Olchon valley lies on the western edge of Herefordshire, hard against the Welsh border, and connects the eastern edge of the Black Mountains to the western foothills of the Herefordshire plain.

The Voyage involves a short (but steep climb) up the main spine of Cat’s Back, examining the scenery of the wider area extending as far as Offas Dyke and including the Red and Black Darrens. You may wish to extend your own journey to include visiting these places. But remember, walking here can involve long trecks over very exposed mountain tops, so make sure you are properly equipped.


Head of the valley

The valley has a wide open aspect and is flanked on its western side by a broad whaleback ridge reaching to nearly 700m in elevation. The Offa’s Dyke footpath runs along the top of this ridge.

Between 757-796AD, Offa was the King of the Anglo-Saxon area of Mercia, which extended across the English Midlands to the border with Wales. Offa’s Dyke is a huge ditch, over 20m wide in places, backed by a high earth bank, extending from the banks of the Severn near Chepstow to Prestatyn on the north Wales coast.


Cat’s Back

On its eastern side the upper reaches of the Olchon valley are separated from the valley of the River Monnow by a distinctive sharp ridge known locally as the Cat’s Back. The ridge may have been named this because it is knobbly in profile in places, like vertebrae on a cat’s back. We will find out why this is later.


Merging at Longtown

Further down river, the topography is more subdued, and the two valleys merge at Longtown.


Creating the landscape

Three main factors determine the landscape of the Olchon Valley.
These are:

1 The Solid geology -the underlying rock
2 The events of the Ice Ages
3 The presence of landslips

We will explore each of these as you climb the ridge.

Solid geology refers to the main rocks (the bed rock) underlying an area, as against the superficial deposits, for example, recent river sediments, soils, or material left behind by the last ice age.


Deep time

Imagine rolling out a measuring tape where each millimetre on the tape represented one year. Offa’s Dyke was created around 1200 years ago, so that would be marked off at 1200 millimetres (1.2 metres) from the start of the tape. The peak of the last ice age at around 25000 years ago would be marked off 25 metres from the start.

The rocks of this area are around 400 million years old, how far along the tape would you mark them? Top of Black Hill, Hay-on-Wye, Birmingham ?

In the app you get the answer by touching the ‘i’ button, here the answer is given in the next diagram.


Task Site 1 Questions

Who or what was Offa?

a) A Welsh chieftain
b) Queen of Ireland
c) The King of Meria
d) An invitation to visit Wales


What is Offa’s Dyke?

a) A border patrol
b) A huge ditch
c) The mot around Offa’s castle
d) A rock intrusion