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| Keywords: The Quarterly journal of the Geological Society of London (14072583161).jpg IN THE CHALK WOLDS OF LINCOLNSHIRE <br> 161 <br> the north This little stream instead of continuing its southerly <br> course turns abruptly to the east and enters a narrow ravine exca- <br> vated out of the Chalk which extends for a distance of about half a <br> mile and then opens into the main valley opposite the village of <br> South Thoresby see fig 1 <br> Fig 1 ” Plan of the country near Swahy Scale 1 inch to a mile <br> The ground occupied by Drift is indicated by diagonal shading <br> The sudden change in the form of the valley below Swaby is <br> very striking Above the village the valley-bottom is some 150 <br> yards wide and the valley-sides have the usual gently sloping <br> outline of chalk hills Below the village the valley is contracted to <br> a trench-like ravine the bottom of which is perhaps 40 yards wide <br> and its sides rise in steep slopes the angle being in many places that <br> of chalk debris viz 35°-38 <br> The wider and older valley is actually continued southward <br> through the village for some distance the barrier of drift being about <br> 400 yards beyond the point where the stream turns aside to enter <br> the ravine This modern continuation of the watercourse is clearly <br> therefore a new cut made through the solid mass of chalk which <br> originaUy formed one flank of the ancient valley <br> It would seem that on the cessation of glacial conditions the <br> stream was able to occupy its former valley as far as Swaby but <br> being there ponded back it made its way over a col in the chalk hiUs <br> which was lower than the surface of the drift barrier and having <br> once taken this course it would naturally maintain and deepen the <br> new channel forming the ravine above described <br> The glacial clays and gravels also occupy for some distance the <br> valley of another tributary which joins the Calceby Beck south of <br> Swaby This stream also has cut into the chalk and runs in a small <br> ravine for a distance of about three furlongs ; but it is only just out- <br> side the limits of the drift area and is not so striking as the valley <br> first described <br> There can be little doubt that the ancient courses of the two <br> brooks are concealed beneath the glacial deposits ; they probably <br> united somewhere near Swaby church and thence the combined <br> Q J G S Wo 157 M 36940932 113697 51125 Page 161 Text 40 http //www biodiversitylibrary org/page/36940932 1884 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 40 1884 Geology Periodicals Smithsonian Libraries bhl page 36940932 dc identifier http //biodiversitylibrary org/page/36940932 smithsonian libraries Information field Flickr posted date ISOdate 2014-04-30 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/14072583161 2015-08-26 05 54 22 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1884 Photos uploaded from Flickr by Fæ using a script | ||||
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