TRANSACTIONS OF SECTION E. 431 



•were once the means of communication between Thome and Hatfield. The 

 fertility of the banks of the Ouse has also been marvellously increased by the 

 system of warping which was introduced early in the last century. Mr. Ralph 

 Greyke, of Rawcliffe, warped 429 acres, and received the gold medal of the 

 Society of Arts in 1825 for his interesting paper on the subject. Warp is a fine 

 light-brown sediment held in suspension in the river. It is soft and silky to the 

 touch and contains numerous glistening scales of mica. The land to be warped is 

 surrounded by a substantial bank. The water is then admitted, and kept there by 

 closing the flood-gates until the second return of the tide, when it is allowed to 

 flow off. The same process is repeated at the next tide, mud being deposited. 

 Thus either a new soil is created or a thin and poor soil improved, there being 12 

 to 16 inches deposited in one season, and even more. Indeed, as many as 10 to 15 

 acres have been known to be covered with 2 to 3 feet of warp during one spring 

 of ten to twelve tides. An expert warp-farmer can, by careful attention to the 

 currents, even temper his soil as he pleases. For the heaviest particles are first 

 deposited, which are those of sand. Then a mixture of sand and fine mud, the 

 most valuable soil. Lastly the pure mud subsides, which is rich but tenacious. 

 The great point is to get the second and mixed deposit over the whole surface, and 

 this is done by keeping the water in constant motion, for the last deposit only takes 

 place in still water. Mr. Caird mentions that fifty years ago Armyn pastures, near 

 Goole, were mostly under water, a breeding-place for wild ducks, and the rest 

 yielded a few cranberries. Now 400 acres are under crops. 



We thus see the important influence that human agency has had in determining 

 the character of the earth's surface, and of what consequence a study of the 

 history of that agency must always be to the comparative geographer. Away in 

 the western hills large artificial lakes have altered the face of the wild moorlands. 

 In the region between Sheffield and Doncaster the forest haunts of Robin Hood 

 have disappeared before the collieries and ironworks, the cultivators and quarriers 

 of modern times. In the levels high cultivation and warp-farms occupy the sites 

 of wide lakes and swamps and dreary wastes, while the courses of the rivers have 

 been altered. Kindred changes have taken place or are in progress in other parts 

 of the world, often upon a much larger scale ; so that a study of the efl'ects of 

 human agency in the valley of the Don is an admirable training for a more 

 extended examination of the facts of comparative geography. 



Our science also occupies itself with the economic statistics of the earth, with 

 the circulation of trade and the products of various regions. Geographers note, 

 for example, the uses of rocks and soils, and the mineral resources of a district. In 

 the millstone-grit range of hills it belongs to geography to record that the lowest 

 grit or kinderscout furnishes blocks for engine beds, for foundations, and reservoir 

 works, but that there are difficulties in making use of it owing to the wild and 

 inaccessible character of a great part of the country in which it is found. We 

 should note that the second grit is quarried for road-paving, and that the first or 

 upper grit (called rough rock) is good building-stone ; that the lowest underclay 

 of the coal measures is a valuable fire clay which is largely wrought; that the 

 Elland flagstones are extensively quarried and cut into blocks and slabs ; and that 

 the magnesian limestone is used for lime-burning and repairing the roads. We 

 should also note the positions and yield of the collieries, the statistics of the iron 

 trade, the agricultural statistics, and the commercial routes, as well as the distribu- 

 tion of population. Many of these vital interests of the region are capable of 

 cartographic illustration. 



This region round Sheffield is fortunate in its writers, who have made the road 

 easy for future students. Your very poets, Ebenezer Elliott and James Mont- 

 gomery, were endowed by nature with geographical instincts. Few districts have 

 had such topographers as Hunter and Eastwood, Holland and Gatty, or so able an 

 antiquary as Mr. Stacye. The authors of the ' Geology of the Yorkshire Coal Field' 

 have furnished you with a detailed history of your rocks ; and in their admirable 

 work on the physical geography and botanical topography of West Yorkshire, Mr. 

 James W. Davis and Dr. Lees have rendered you an inestimable service. From 

 their work I have derived many of the ideas and a great deal of the information 



