i 



CiRC 109. 



oi Sihho(his ohsctirin; 'in situ' I referred them to the ^Nlagncsian Limestone series. 

 The occurrence of red beds at llie lop of the lower series and at the base of the 

 overlying series may be studied in this district under favourable circumstances, as the 

 several members of both the u]iper and the lower series differ so much in character 

 that various hypotheses can be put to the test. One fact that must be taktn account 

 of is that a land surface which has been exposed to all the oxidizing agmciesof 

 subacrial denudation was submerged and covered by newer deposits much of the 

 material of which was derived from this oxidized superficial deposit of the sinking 

 land. It is a notable fact that the red stained rocks of the older system and the 

 red beds at the base of the new find their counterpart at each great stratigraphical 

 break in the geological sequence. The presence of calcareous beds always inter- 

 feres with this development of colour, 



The base of the Magnesian Limestone series may be examined here and there 

 between Tontefract and the river Aire near Weldon, both south and north of 

 which locality quarries have been opened in the Lower Limestone, which here dips 

 at a small angle in an east-south-easterly direction. From Ferry Bridge the Middle 

 Marls, dividing as its name implies the Lower from the Upper ?^Iagnesian Lime- 

 stone, trend irregularly in a south south-easterly direction. The Upper Magnesian 

 Limestone is exposed in quarries nt>ar Knotlingley and Woniersley, and on tlic 

 north and south side of the patch of Upper Marls which occm-s about half way 

 betw^een those towns. It will be observed that while the marls and sandstones are 

 generally red the limestones are yellow^ The different texture of the Upper and 

 Lower Limestone may also be noted. In the characteristic fossil the Schizodus 

 {Axijiiis) some will see the forerunner of the Alesozoic Trii^onia. Over the plains 

 to the east of Ferrybridge it is inferred that the Eunter Sandstone occurs at a small, 

 depth, liut the 'drowned valleys' are silted up. and sands, some of marine 

 origin and some here and there probably eolian and afterwards levelled under water, 

 occur in low banks and terraces all over these ' regiones inundatLV.' Ferhaps tlie 

 most interesting subject for investigation, and one which can nowdiere be so_ well 

 studied as here, is the mode of formation and character of the natural and artificial 

 "warp. The Huml)er and its tributaries carry a great quantity of sediment in sus- 

 pension. This tidal silt is being carried to and fro, stirred up and transported out 

 into the Estuary wdth every freshet from the highei ground and every ebb ; borne 

 back by every flowing tide, but settling to the bottom between whiles, whenever 

 the velocity of tlie currents is sufficiently reduced ; while now- and then the river 

 overflows its banks and throws down, the coarser first, the finer later,_ wdien the 

 water has spread out over a wider area. Thus these rivers, like the Mississippi and 

 the Po, have raised their banks, and also in time their bed, and ships may be seen 

 full sail floating above the level of the surrounding corn-tields. In later times man 

 interfered and raised the banks to control the river and give a sound roadway for 

 the horses that towed the barges. When their banks gave way thr surrounding lower 

 ground was of course submerged, but it was found that the land was so improved 

 by the silt thrown down from the turl)id water that this compensated the farmer for 

 his temporary loss; and soon he adopted the plan of renovating impoverislicd land 

 by turning on the tidal w-ater over large areas enclosed within eml^antanents, regu- 

 lating the amount and distribution of the sediment by a regular system of sluices 

 andartilicial channels. The deposit thus laid down from the nature of the case 

 occurs in layers ; the coarser settles first, the finer last ; and thus a lammated clay 

 is formed, each tide or inrush being marked by the change of sediment — and the 

 time allowed for its precipitation l;y the thickness of the layer just as at the bottom 

 of the mill-pond the Sundays were noted by tlie thicker l)ands of mud. 



BOTANY.— The Botanical Section will be officially represented by its 

 President, Mr. V. F. Lee, and its Hon. Sees., Messrs. Albert H. Pawson, M. B. 



Slater, F.L.S., and Charles Crossland. 



Mr. George Roberts writes that the following plants have been found in the 

 ^\\^iUQ,\.;—Lyii,!iaihm niii/n/nilana, Melilotus officinalis, PaTnassia palustris, 

 Geum rivalc, Eshiuui viil-arc, Chlora pcrfoliata. Reseda luiea, Sagiltaria sagitti- 



\ 



folia, Maha Nioschata, J'iola odoraia, V. /lir/a. Genista iinctoria, Anihyllis 

 ■viilnei-aria, Campanula lalifolia, Nepcia cataria, Lysimachia vulgaris, Veronica 



^nagallis, Asplcninm rnia-nniraria. 



Mr. b Neale records the following plants as occurring near Ferry Fryston 

 Church, in ditches or on the railway or in water meadows ■.— Utricnlaria neglecta, 

 J^of/onia, Polyonuin bistorta, Typha, PJastiirtiuin pahistre, Lysiniaehia navi- 

 iniilaria (extre'mely abundant), Lythruin salicaria, Apiuni noJijhni;/i, O-li/anthc 



