1 50 Geological Society. 



III. Carboniferous series of Clare. 



The clay-slate formation in this county is bordered by a belt of old 

 red sandstone, to which succeed, in ascending order and conformable 

 position, the mountain limestone and coal measures, both of which 

 occupy flat and undulating hills, and the strata usually dip from the east 

 of north to the west of south ; but seldom at a greater angle than 5°. 

 The best sections are seen in the cliffs of the west coast, where shale, 

 sandstone and sandy-flag-stone overlie limestone. Coal, however, 

 is there of very rare occurrence, and when disclosed is of very indif- 

 ferent quality ; and the author infers, that the lower part of the series 

 in the county of Clare is comparatively poor in this mineral : he, how- 

 ever, suggests that the best chances of discovering valuable seams 

 must lie in the elevated regions of Mount Cullun j where if coal be 

 found, the beds being nearly horizontal, it might be worked with ad- 

 vantage. 



The Memoir concludes with some observations on the distribution 

 of diluvial matter in the South of Ireland. 



1. Boulders, gravel and sand, derived from the transition series are 

 lodged along the borders and sides of the mountains in Kerry. 



2. In a small district of Limerick and Tipperary, situated between 

 the Gaultees and Slieve-na-muck, the rolled debris consist not only 

 of portions of the contiguous rocks, but contain also porphyry, which 

 is not to be found in situ near the vicinity of Pallis Hill. 



3. In the peninsula of Renville, near Galway, the surface of the 

 carboniferous limestone is strewed over with numerous boulders of 

 red and gray granite, syenite, greenstone, and sandstone, which must 

 apparently have been conveyed from the opposite side of the bay of 

 Galway. 



June 18. — Robert Dawson, Esq. of the Royal Engineers, and em- 

 ployed on the Ordnance Survey of Ireland, was elected a Fellow of 

 this Society. 



A letter on the Basin of Alhama, in the Province of Granada, in Spain, 

 being the second of two letters addressed to R. I.Murchison, Esq., Sec. 

 G.S., F.R.S. &c,by Col. Charles Silvertop, F.G.S., was then read*. 



The basin of Alhama is situated about 50 miles to the south-west of 

 the basin of Baza, which was described in the former letter. It occupies 

 a large circular area, bounded on the south and east chiefly by the 

 primitive chain of the Sierra Nevada, and on the north-west and 

 south-west by ridges of nummulite-limestone. The greater diameter 

 of the basin, namely, between the village of Huerta de Santillana on 

 the north, and the ridge near Alhama on the south, is about 36 miles ; 

 and the smaller diameter, between the village of Escujar on the east, 

 and the town of Loja on the west, is about 30 miles. The principal 

 river traversing the basin is the Genii, which takes its rise in the 

 Sierra Nevada to the east of Granada ; and having received all the 

 minor streams which water the basin, it passes through a chasm in 

 the nummulite-limestone near Loja, and afterwards unites with the 

 Guadalquiver. 



* For the first letter, see Phil. Mag. and Ann. of Phil., vol. vii. p. 453. 



The 



