464 PKOF, E. J. GAEAYOOD OK THE LOWER CAEBONIEEROUS [DeC, 1912^ 



The index-fossil often occurs in reef-like masses up to 2 feet 

 in diameter, which do not, however, form true coral-reefs, for 

 they are often seen to lie in an inverted position : showing that 

 they grew loosely attached to the bottom, and readily drifted after 

 death. This fact in itself testifies to the prevalence of shallow- 

 water conditions and to the presence of wave- or current-action at 

 this period. Caninia suhihicina first enters at this horizon in the 

 Shap District, and persists to the summit of the M.ichelinia Zone 

 in the Arnside District. At llosgill and Ravenstonedale Moor, 

 in the Shap District, we meet with the earliest examples of 

 papilionaceous forms of Chonetes. The band is most fossiliferous in 

 the Ravenstonedale District, wliere the lower layers are marked by 

 the abundance of well-grown specimens oi Fistvlipora incmstans. 



Geographical distribution. — Between Bampton and the 

 Dent Fault in the Shap and Bavenstonedale Districts, an almost con- 

 tinuous outcrop (Shap village is built on the outcrop of this baud). 

 Along the western escarpment, and in the Grayrigg outlier, in the 

 Kendal District. Near Broad Oak in the Grange District. In the 

 Arnside District it has practically thinned out, and is absent in the 

 Turness District. In the Westmorland Penniues it occurs onty 

 under Eoman Fell, and serves here to mark the time when this 

 district was first submerged under the Carboniferous Sea. 



The beds immediately overlying the Thysanophyllam Band in 

 the Shap District consist of a few feet of compact and oolitic lime- 

 stones, occasionally abounding in specimens of Belleroplion. The 

 beds thicken, and become more shaly when traced into the Ilaven- 

 stonedale District. Above Brigsteer in the Kendal District they 

 contain silicifted specimens of CyatliopliylJum cf. midtilamellaUnn. 



(ho) The Brownber Pebble-Bed (Syrioigothyris- 

 cuspidata Band). 



This band depends for its value as a stratigraphical horizon 

 chiefly on its lithological structure ; at the same time, its fauna is 

 decidedly characteristic. In its typical development it is confined 

 to the Shap-Bavenstonedale and Pennine Districts, but it can just 

 be traced in the Kendal District. The band is marked by a series 

 of oolitic limestones and calcareous grits averaging 20 or 30 feet in 

 thickness, enclosing layers of false-bedded conglomerate. This 

 conglomerate is composed of white quartz-pebbles averaging about 

 an inch in diameter (though occasionally much larger), embedded 

 in an oolitic matrix. The layers of pebbles are very inconstant, 

 and thicken and thin laterally. The band represents the most 

 pronounced development of oolite in the North -Western Province. 

 The quartz-pebbles appear to have been introduced by strong 

 currents setting from the Pennine Area lying to the east, which 

 was then being submerged for the first time and was undergoing 

 marine denudation. The deposit is thickest in the neighbourhood 

 of lioman Fell, and here the quartz-fragments are on the whole 

 largest and the development of oolitic structure most pronounced. 



