600 
Proceedings of the Royal Society 
must have stood up as an important geographical boundary in early 
Carboniferous times, this “ cement-stone ” type of sedimentation 
also occurs but less extensively, and with a curious blending of 
characters lithological and paheontological, which give to the basin 
of Eskdale and Liddesdale an exceptional geological interest. 
In this district the following general section in descending order 
is observable : — 
General Section of the Carboniferous Rocks of Eskdale 
and Liddesdale. 
Feet. 
Scar (Scaur) Limestone of Northumberland. 
11. Fell Sandstones probably more than . . 1000 
10. Horizon of Plashetts and Lewisburn coals, 
9. Upper cement-stone group, about 300 to 400 
8. Horizon of Canobie coals, . . . 800 
7. Gilnockie (marine) limestone group, . 400 or 500 
6. Zone of volcanic tuff, . . . 10 to 20 
5. Scorpion Shales, .... 50 
4. Zone of volcanic tuff and porphyrite, . 50 to 100 
3. Sandstones of Irvine Burn, . . . .200 
2. Lower cement-stone group (Tarras), . 200 to 300 
1. Whita Hill Sandstone, . . . 500 to 600 
Volcanic band (Porphyrites, &c.), . . 40 to 100 
Upper Old Eed Sandstone lying uncom- 
formably or Upper Silurian rocks, . . 300 
A few remarks may be offered upon the characters of these 
successive platforms. 
1. The White Sandstone, well seen on Whita Hill above Lang- 
holm, consists chiefly of massive beds of hard white, yellow, and 
pinkish calcareous sandstones, often full of concretions (“ galls ”) of 
a pale clay, which dropping out gave a honeycombed aspect to 
weathered surfaces. The sandstones are sometimes separated by 
thin shale partings, and occasional seams of impure limestone 
or cement-stone. 
2. In the Tarras water a lower group, of true “ cement-stone ” 
facies, attains a thickness of probably from 200 to 300 feet. It con- 
sists of blue clays and shales with impure limestone or cement-stones 
and beds of shaly sandstone. These strata have yielded numerous 
remains of fishes, eurypterids and ostracods, but none of the 
ordinary marine organisms of the Carboniferous limestone bands. 
