296 Capt, Grant on the Geology of Cutch. 



the irrigating beds, and four or five measures of potash. It is not so much esteemed in the 

 Bombay market as that brought from China, on account of its yellow tinge. 



Some of the marls resemble chalk, being white, and soiling the fingers; and some are very 

 calcareous, whilst other varieties scarcely effervesce with diluted muriatic acid. In one mass I 

 found a very minute specimen o( Buccinum pumilum (sp. n. PI. XXIII. fig. 1.). These marls also 

 occur of every variety of colour as well as texture ; some of them consisting of innumerable 

 thin laminae curiously twisted and arranged in the most intricate manner ; and others of a kind 

 of breccia, composed of small broken portions of marls. Several dykes of basalt cut through 

 these beds ; the whole presenting a most confused assemblage, partly due to natural causes, and 

 partly to the numerous mines which have fallen in. One of the banks has been burning sponta- 

 neously for several years, in a similar manner to that at Ruttrea, and apparently from the same 

 cause. The exact geological position of these marls I could not determine. 



3. Red Sandstone. 

 1 have mentioned a red sandstone formation, which may be described now. 

 It occurs to the southward of the coal series, and is separated from it by a 

 low range of hills about six miles broad, composed partly of basaltic rocks, 

 and partly of a variety of porphyry. This sandstone is regularly stratified, 

 and has the same dip and inclination as the sandstone and coal series, but dif- 

 fers very materially from it, in being much softer, generally finer-grained, of a 

 vast variety of colours, and by containing no organic remains. Associated with 

 the sandstone are beds of clay, varying in colour from purple to deep red. 

 One of the beds is aluminous, and has been burning spontaneously for a long 

 period. The smoke issues from a deep crevice in the bank, and the fumes 

 are highly sulphureous. A stick thrust into the crevice soon ignites, and the 

 whole bank has a burnt appearance ; the red clay, which rests immediately upon 

 the stratum, having been converted into a perfect brick, and the other varie- 

 gated clays having been variously acted on. Although this bed would yield a 

 large per centage of sulphate of alumina, it has never been worked. The 

 strata dip at an acute angle to the south, and are covered, in that direction, by 

 beds of gravel, succeeded by others of sand and soil, which extend to the sea. 



4. Laminated Series or Upper Secondary Formation. 

 Alternating strata of slate-clay, limestone-slate, and occasionally slaty sand- 

 stone, constitute this formation. The more calcareous beds are very hard 

 and compact, whilst some of the others are very earthy and friable. In many 

 of the calcareous slabs, the upper and under surfaces are argillaceous, hard, 

 and compact, but the centre is a grey limestone, which takes a good polish, 

 and might be used for lithography. The slate-clay is of a dark blue colour, 

 and generally peels in thin flakes, leaving a flat, lenticular nodule or centre. 

 In many places, vast thicknesses of this laminated slate-clay occur without the 



