170 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 6, 



Thus then we have three beds of peat (2, 4, and 6), separated by 

 two strata of marine clay (3 and 5) . 



In another place, four of peat and four of clay were exposed, but 



1 chose the spot above referred to because the formations were hori- 

 zontal, more regular, and easily measured. In the peat we find the 

 oak, beech, birch, alder, hazel, and crab-tree still easily identified. 

 The bark of the birch is little changed, that of the other trees has 

 lost much of its character. 



I have not met with any of the Coniferse ; but reeds and grasses 

 abound. In the peat I could find nothing besides the vegetables 

 composing it ; the same plants occurring in the different beds, but 

 less distinct as they became more distant from the surface. 



The gravel (No. 1) in the dock-section, has, I think, been brought 

 down from the very large accumulation of that material at Landore, 

 If mile N., where water has cut through a deep deposit which 

 appears to me to be an ancient moraine. 



The origin or parent source of the gravel must be sought in the 

 sandstones of the coal-measures, which have contributed the largest 

 portion ; the millstone-grit 20 miles N., next in abundance ; the 

 limestone 21 miles N., pieces of which are rare ; and the Old Red 

 Sandstone, 22 miles N., nearly as frequent as the millstone- grit. 

 The size generally ranges from small gravel up to large shingle ; but 

 boulders have occurred, some large enough to require blasting : one 

 of these was hmestone. 



Appendix. — On the Sunken Portion of Swansea Bay. 



According to the ancient legends before referred to, Swansea Bay 

 was once land, the sea-boundary running from the Mumble Point to 

 near Aberavon, a distance of 7 miles. The present high-water line 

 runs far into the land, there being on an average 3 miles between the 

 actual and the traditionary limit of the sea, more than half of which 

 is dry at the low- water of average spring tides. The western portion 

 is said to have been covered by a forest called Silverwood. It is 

 also stated that the Neath River joined the Swansea River near 

 Swansea, and that their waters flowed out to the sea close to the 

 Mumble Rocks. 



How much of the legends may be true, we will not stop to inquire ; 

 but in the dock-cutting, I found the beds of two rivers and their 

 junction, while the stool and root of many a noble tree covered at 

 every high tide tell of the ancient forest. 



The peat and clay extend along the shore 4 miles to the W. and 



2 miles to the E. of Swansea ; further on towards the Neath River 

 the sand has accumulated to such an extent that I can only infer 

 their continuity from the water being thrown out with considerable 

 regularity, as if by the out crop of those impervious beds, and at the 

 same level. 



I know not how far these formations extend inland, but the upper- 

 most is traceable from the shore for distances varying from a few 

 yards to more than a mile (at Crumlyn Bog). 



