TRANSACTIONS OF SECTION E. 719 



tributaries Ne than and Harpersgill, &c. It is shown that a perfect series of transi- 

 tions can be found from the vertical cliff or scaur left by the river to the continuous 

 steep slope, which is characteristic of the valley-sides throughout this neighbour- 

 hood. 



The vegetation is shown to control this slope formation throughout. The 

 vegetation covering the space at the base of the cliff forms very rapidly. 

 The annual formation of wood and other tissues is shown to be very great in this 

 sheltered and moist situation (as compared by measurements with the growth of 

 the same plants in more exposed positions). Any falls Irom above, such as stones 

 or rock, earth and vegetable matter washed or blown down, accumulate at the 

 base of the precipice o.- scaur, and are at once covered over by the vegetation. Thus 

 a steep sloping surface is formed which gradually extends up the side of the cliff 

 until eventually the characteristic V-shape of the ravines is produced. 



Measurements showing the average slopes in at least four separate ravines 

 were given. 



The undermining of the rock below the fringe of vegetation is shown in some 

 cases to result in a slope which eventually unites with the accumulation from below 

 to form the characteristic angle of inclination. 



The character of the vegetation of course alters greatly the tenacity of the 

 covering formed by it. Thus trees form an exceedingly strong network of roots, 

 as is shown by the example at Eenmuir, where landslips affecting the whole face 

 of the slope have appeared through the original trees having been destroyed. 



An attempt was made to give measurements of the average tenacity of the 

 vegetation crust in a few cases, provided the practical difficulties can be overcome 

 in time. 



Ilolmlands orjlats or valley floors. — Character, value, and constitution of the 

 holms at different points of the Clyde contrasted, and their differences shown to 

 depend on the mixtures of soils and proportions of organic material. The formation 

 of these flat lands is shown to depend chiefly on the work of certain marsh plants, 

 of which Scirpus lacustrif, Fhragmites, Vmtcheria, Poufluitati-s, and various sedges 

 are the mo.st important. The difficulty of tracing their action arises from the 

 extent to which draining has been carried on, but observations are given illustratin;:? 

 the species mentioned, and showing that the amount produced in a single year is 

 by no means an inconsiderable quantity. 



Shingle beds. — The shingle beds and the manner in which they are covered by 

 vegetation is also discussed shortly. 



Au attempt is made to show on the map the approximate boundary of what 

 was at one time river and estuarine marshes. The difficulty of deciding upon the 

 exact boundary line is shown to depend upon the amount of boulder clay and drift 

 which closely resembles the ordinary alluvium. If time is left, au attempt will be 

 made to compare the alluvial formations of other countries with those of the 

 Clyde. 



2. The Scottish Natural History Society's Scheme for the Investigation of the 

 Forth Valley. By Marion Newbigin, D.Sc. 



The paper gives au account of a scheme which has been undertaken by the 

 Scottish Natural History Society at the suggestion of Sir John Murraj-. It is 

 proposed, first, to arrange, in a readily availaljle form, references to papers already 

 published on the natural history of the Forth Valley, includuig its botany, zoo- 

 logy, and geologj' ; secondly, the Society proposes to utilise its various sections and 

 the labours of its individual members in the acquisition of a mass of detail in regard 

 to the existing organic conditions in the valley of the Forth, with the primary object 

 of providing a basis of fact upon which conclusionsmaybe later established, although 

 the opportunities of the work as a means of training observers will not be lost 

 sight of. It is hoped that the work may be carried out in such a way that the 

 conditions of existence of the most important organisms within the area may be 

 readily ascertained by reference to the Society's records. 



