LOWER LIAS: CUMBERLAND. 183 
The evidence obtained in this area, goes to show that we have, 
resting on the Red Marls and Rhretic Beds, a succession of 
Lower Lias beds that exhibit similar characters to the beds in 
Gloucestershire and Worcestershire, and afford evidence of the 
zones from that of A. planorbis to that of A. Jamesoni or 
A. Henleyi. 
Cumberland. 
Extending over a considerable tract to the west of Carlisle, 
there is an outlier of the basement-beds of the Lower Lias. 
The area is for the most part a plateau, and this is more marked 
between Aikton and Great Orton than further east. Geologically 
speaking it is a somewhat dreary country, for the most part 
covered with a thick accumulation of earthy Drift gravel; and 
we have therefore the same difficulty in fixing the limits of the 
subjacent Lias, as in the larger Drift-covered tract in Shropshire 
and Cheshire. 
The presence of the dark shales of the Lias in this part of 
Cumberland, lias led during the past 250 year* to a number of 
borings in search of coal ; but the identification of the Lias, 
originated with Mr. R. B. Brockbank, who found Ammonites and 
other fossils in the shales exposed in the banks of Thornby Brook, 
south-east of Aikton. The specimens were sent to E. W. Binney, 
who in 1859 published an account of the strata; he noticed the 
presence also of limestones with Lower Lias fossils at Quarry- 
Gill, near Aikton, where the stone had formerly been excavated.* 
At VViggonby a bore-hole had been put down 120 feet into dark 
shales, and near Great Orton a boring made in 1781, reached blue 
stone below the Drift, at a depth of 18 feet from the surface, and 
after passing through " different stone, mostly bluish," to a depth 
of 228 feet, passed into the New Red rocks. 
The evidence has been carefully studied by Mr. T. V. Holmes, 
who constructed the Geological Survey map of the area ; and he 
discovered a third exposure of dark shale with bands of limestone, 
in a brook between Great Orton and Flat. The Lower Lias 
consists of shales with bands of limestone, some of them sandy and 
micaceous ; and it has yielded Ammonites Johnstoni, Grypheea 
arcuata, and Ostrea. 
The Ammonite has been found at the three exposures of the 
Lias, and thus there is no evidence to show that any beds above 
the zone of A. planorbis are preserved in the area. 
The question is whether any of the strata passed through in the 
Orton boring, can be referred to the Rhastic Beds. Mr. Holmes 
remarks lhat their existence " in this district is, and is likely to 
remain, an open question." He has expressed the opinion that 
the Lias probably rests on the Gypseous Shales west of Great 
Orton, and on the Kirklinton Sandstone east of that village ; the 
* Quart. Journ. Geol. Sec., vol. xv. p. 550 ; see also Sedgwick, Trans. Geol. Soc., 
ser. 2, vol. iv. p. 383. 
