428 report— 1879. 



five miles in width, right across Yorkshire from the North Riding to Nottingham- 

 shire. Wherever the rivers force their way across this limestone, we find picturesque 

 scenery. Outside the Don valley we have Jackdaw Crags, near Thorparch, rising 

 over the river Wharfe and Anston Rocks to the south, within the Trent drainage 

 system. On the south-east bank of the Don also there is a bold escarpment ; and 

 the Went is, on either hand, bounded by precipices of limestone, where it cuts its 

 way through the Permian formation. 



Eastward of the magnesian limestone, which forms a distinct escarpment across 

 the river-basin from north to south, is the Trias formation, consisting of the deep 

 red Bunter Sandstone on which the town of Doncaster is built. But the Trias 

 only occurs in patches, and is generally overlaid by the muddy deposits from the 

 Humber, on which are the wide expanses of level peat moss, ranging from 1 to 

 20 feet in thickness. In cutting through this peat, cones of Scotch firs have 

 been plentifully found, and in the lower layers there are stumps of trees firmly 

 rooted into the sand, proving that a forest once grew there. 



It will have been seen how the geology of the Don basin helps us to understand 

 its physical features. The different formations decide the position of the water- 

 parting, the direction of the drainage, and even the character of the scenery.' A 

 knowledge is often desirable, not only of the surface rock, but also of the formation 

 which underlies it. When, for example, the magnesian limestone rests on a hard 

 sandstone, its escarpment often rises to more importance than when its foundations 

 are on a softer rock. 



The distribution of plants, which is another and a very interesting branch of 

 inquiry in the study of physical geography, is decided chiefly by climate and alti- 

 tude above the sea, but it also depends a good deal upon the soils and the forma- 

 tions from which they come, and here again geology is useful to the geographer. 



On the millstone-grit mountains we find high Alpine plants, but not in such 

 abundance as in other parts of the Penine range to the north, when it reaches a 

 higher altitude, and where the mountain limestone comes to the surface ; and we 

 are told that the characteristic of this formation is many individuals but few 

 species. _ The ivy-leaved campanula is found by the moorland rills, pennywort 

 grows wild at Bradfield, and the hills contain a rare fern (Asplenium lanceolatum) 

 discovered by Dr. Gatty, the locality of which is wisely kept a secret from ruthless 

 collectors. But the oak is the prevalent and self-sown tree on this gritstone soil, 

 and is_ indigenous in the beautiful woods of Wharncliffe. Elliot sings of the 

 ' Rivelin Oak,' and Evelyn, in his ' Sylva,' records the gig-antic size of some of the 

 trees in Sheffield Park. 



In the valley of the Dearne, and generally over the coal measures, the flora is 

 not rich. The alternations of shales and clay hold the rainfall above them, instead 

 of allowing it to filter quickly away, and cause a wet and stifl' soil. In the 

 Permian formation, on the other hand, there are many uncommon limestone- 

 loving plants, and the levels beyond Doncaster abound in marsh plants. 



A cursory study of the floras in these several formations, guided by the labours 

 of botanists, will enable the geographer to appreciate the causes which influence 

 the distribution of plants, and the various effects of soils, altitude above the sea, 

 moisture and temperature. In extending his view, he would compare the flora of 

 the Don river-basin with those of neighbouring basins, and thus obtain a know- 

 ledge of the_ comparative flora of a wider region, and of the influences which regu- 

 late its distribution. There cannot be any better training for the study of botanical 

 geography on a broader and more general scale. 



Meteorology is also an important element in the study of physical geography, 

 not only as determining climate, and its • influence on plant distribution, but as 

 affecting the hydrography of a region, and the amount and rapidity of denudation. 

 Its study should not be confined to mere registration, the barren results of which 

 have too often been demonstrated. It is very seldom that reliable observations 

 range over a sufficiently long time to give useful results even in countries where 

 there is a trigonometrical survey (the height of civilisation), and scarcely ever in 

 less advanced districts. In Mr. Harrison's interesting history of the flood of 1864, 

 I notice a record of the rainfall in the Dale Dyke valley, varying from 46 inches 



