156 Archdeacon Verschoyle on the Geologi/ of the North Coast of 



bedded in an argillaceous cement. It occupies the spaces between large 

 masses of the same rock, thrown confusedly together. The edges of the 

 beds are elevated and much fractured, while their recurrence to the north, to 

 which point they rise, indicates a subsidence or fault ranging east and west. 

 The beds of peat and bog-timber, found below high-water mark in Killalla 

 Harbour, may be connected with the fault. Near this place the sandstone 

 emerges from beneath the oolite in rude columnar masses, much disturbed, 

 and forms the commencement of the grit and shale beds described under the 

 next head. 



C. Calcareous and Argillaceous Shale and Grit. 

 The mountain limestone rests on alternating layers of sandstone, slate clay, 

 and argillaceous limestone, except where the oolitic strata intervene ; and the 

 lower beds of grit, graduate, in some places, so insensibly into the subjacent 

 quartz rock, that the limits of the two formations are very difficult to determine. 

 At the western boundary the transition is gradual, and were it not that the strata 

 of quartz rock at Glen Lassera, are unconformable to the beds of sandstone, the 

 demarkation could scarcely be ascertained. The conglomerate of the old red 

 sandstone is also absent there ; but along the foot of the Ox Mountains, it is 

 interposed between the grit and shale beds and the older strata. To detail 

 the succession of layers is impossible, but two examples, taken from Ross and 

 Moyne, may be instructive; and Mr. Griffith's Memoir on Mayo, in the Re- 

 ports of the Bog Commissioners, made in 1814, furnishes the details at Bal- 

 horig in Erris*. 



Section at Ross, near Killalla. 

 Ft. 



Sandstone, highest bed 12 



Claystone 5 



, 



, 



, 















Clay parting .... 



Wacke 



Yellow Clay 



Wacke 



Red Clay 



Green, Sandy Clay 



Claystone 



Shale 



Sandy Clay 



Wacke 



Sandy Clay 



Brought forward 



Schistose Sandstone 



Claystone 



Schistose Claystone 



Wacke 



Sandstone, with clay nodules im- "l 



bedded / 



Yellow Clay 



Wacke and Sandstone, with wood 1 



in a bituminized state / 



Black Shale 



Claystone (lowest bed exposed). . 



Ft. In. 



24 6 



2 



6 



1 



5 



4 



9 

 8 



1 6 

 10 



* Report, p. 179. 



