TRANSACTIONS OF SECTION C. 649 



of the ice-cap. But it is equally possible that similar morainic ridges may arisfr 

 under the ice-cap, or withia it. 



At any rate, it seems almost impossible to explain the formation of Ssar by river 

 action. The cores of the Kangasala and Yviiskyla Ssar, with their immense scratched 

 boulders, certainly have not been deposited bi/ rivers. Nor the unstratified, un- 

 washed, and unsorted core of the Upsala Ss. This latter, which runs from a level, 

 of 500 feet to 120 feet, next raises to a level of 207 feet, descends to Lake Malar 

 in the level of the sea, and creeps again to a level of 180 feet, cannot have been 

 made by a river. Even under the ice a river would mine its channel in the line of 

 least resistance (eastwards in this case), instead of running uphill. No river could, 

 moreover, have so steady a channel, a fenr hundred feet wide, as to make such a 

 ridge ; it would have changed its channel in the course of time in the ice as well,, 

 just as it does it in a rocky bed. 



The latest researches of Finnish geologists, showing the existence of two fron- 

 tal moraines of the ice-cap, nearly parallel to the northern shore of the Gulf of 

 Finland, and probably of a third I'urther north (about Kuopio) were next referred 

 to, as a parallel to the frontal moraines discovered in America. 



5. T/ie Clicdk)/ Boulder-clay and the Glacial Phenomena of the Western- 

 Midland Counties of England} B>j H. B. Woodward, F.R.S. 



The general distribution of the Chalky Eoulder-clay is first stated, and its 

 limits in Southern and Western England defined. The author then deals with 

 certain phenomena of especial interest, such as the wide dispersal of the chalky 

 detritus in the drifts, the disturbance of the underlying strata, the occurrence of 

 large blocks or ' cakes ' of the local formations among the glacial deposits, and 

 the intercalation of sand and gravel with the boulder-clay. 



In the West-Midland counties, the glacial phenomena of which have not yet 

 been thoroughly examined, there is a marginal area bordering tbe strongly 

 glaciated regions to the east and north-east. This has not been afl^ected by the 

 later stages of the Glacial period, as the Chalky Boulder-clay is succeeded by 

 modified drift in the form of valley gravels and loam, with the remains of 

 mammoth and associated fossils, which merge into the estuarine and marine 

 deposits of the Severn Valley. In sketching the probable southern and western 

 limits of the Chalky Boulder-clay in this region, the author remarks on tbe absence 

 of drift from certain elevated tracts a s indicating that the land-ice may have beea 

 locally arrested by them and divided into lobes and tongues which invaded the 

 lower ground. Previous to this glaciation the main features of the country seem 

 to have been aa at present, but there was no doubt a thick covering of 

 weathered rock and rubble on the surface, and this material would be readily 

 frozen into the base of a sedentary ice-sheet. In general the chief effect of the 

 ice has been to degrade the surface features rather than to efface them. 



The glaciation does not seem to have affected the Cotteswold Hills, which are 

 flanked with thick accumulations of local rubble, explicable as the result of the 

 disintegration and redistribution of the surface layers during alternate frost and 

 thaw, as suggested by Witchell and Lucy ; Edgehill also appears locally to have 

 arrested the land -ice. 



Although the chalky ingredients of the Chalky Boulder-clay are present over- 

 wide areas, there is much local variation in the other material, according to the 

 nature of the underlying rocks. The new railway cuttings of the Midland branch 

 Railway east and west between Bourn and Saxby, and those of the Manchester, 

 Sheffield, and Lincolnshire Railway north and south between Catesby and Quaia- 

 ton Road, near Aylesbury, have furnished good examples of this variation. 



If the weathered soil and subsoil were frozen into the sedentary ice, the dis- 

 turbance of the underlying rocks, of which many instances are cited, might be 

 produced during the movement and shearing of these basal layers. The debris 

 thus removed might rise by overthrusts into higher horizons in the ice, and ba 



' Geol. Mag. Dec. 4, iv. p. 485. 



