374 Studies on the Palceozoic Soils of North Wales 



long nearly a century ago^. The town of Portmadoc and the village 

 of Tremadoc are situated on this former estuary — still known as Traeth 

 Mawr. Agriculturally and otherwise the reclamation of Traeth Mawr 

 has not been remunerative. It is possible however that the sandy soils 

 may be suitable for market gardening. At present they carry rather 

 poor grass. 



Small areas of this type of alluvium occur also at Ystumllyn near 

 Criccieth where a shingle bank has cut of! a creek from the sea leaving 

 about 200 acres of poor sandy soil often flooded in wet weather, and at 

 Llanfaglan near Carnarvon where small areas have been reclaimed 

 around Foryd Bay. 



As may be expected, from their origin, the estuarine alluvia show 

 considerable variations in composition. An average analysis will there- 

 fore have no meaning. The analyses of two extreme types are shown in 

 the general table. C23 is a fairly heavy loam from Dinas Dinlle near 

 Foryd Bay; C24 is a sandy soil from Portmadoc. Both are under 

 grass. It is noteworthy that the grass on C24, in spite of the coarse 

 nature of the soil, is passable in quantity and quality. The rainfall 

 here is over 45 inches per annum. 



(h) Fluviatile Alluvium occurs in the valleys of Conway, Clwyd and 

 Elwy. In the first two of these valleys the alluvium occupies a con- 

 siderable area — probably well over one thousand acres in each case. 

 In the valley of the Elwy the alluvium is confined to thin strips along 

 the river bank. These soils are chiefly under permanent grass and are 

 considered fertile, particularly in the Conway valley. In the valleys 

 of Conway and Clwyd considerable tracts of waste occur where the 

 drainage is imperfect. 



In composition they shoAV considerable variation and no. purpose 

 will be served by giving the average analyses. Three sub-types can 

 however be recognised and an analysis of a soil of each type is given. 



Dolben D7 is typical of the lighter type of alluvium found along 

 the banks of the Elwy and in the upper parts of the Vale of Clwyd. 

 Llanrwst D51 is typical of the Conway alluvium and is distinguished 

 by its high proportion of silt and fine silt. It contains comparatively 

 little clay and is fairly easily worked. Lleweni D 10 is typical of a large 

 stretch of heavy alluvium in the Denbigh district. As will be seen, it 

 contains a remarkably high proportion of fine silt and, for North Wales, 

 a large amount of clay. It is, agriculturally, a true clay. 



^ This embankment forms the subject of several pages of Thomas Love Peacock's 

 Headlong Hall. 



