Part of Gloucestershire and Somersetshire. , S49 



usual ingredients, I have found also pieces of oolitic limestone, the origin of 

 which is evident from what has been already mentioned (§ 22.) respecting 

 the oolitic character of the carboniferous limestone in certain places. 



§ 27. The general characters of the new red sandstone in England, may 

 be collected from the instructive papers of Dr. Holland, Mr. Horner, Mr. 

 Winch, and Professor Buckland, in the 1st, 2d and 4th volumes of the Geolo- 

 gical Transactions. Wherever this formation appears in the Tortworth di- 

 strict, it is commonly in the form only of red indurated clay or clay-marl, sel- 

 dom acquiring the firm consistency of sandstone. In composition and general 

 character it agrees so strikingly with the clay and clay-marl of the old red 

 sandstone formation, that the description which has already been given of the 

 latter may in a great measure be applied to it. The tenacity of the compound 

 in both, is various ; arising from the different intermixture of ferruginous 

 matter with clay, marly clay, minute sand, and glimmering particles of mica; 

 and the same delineations of blueish and greenish colours occur in it, traversing 

 the reddish brown or brownish red ground, in the form of streaks in all direc- 

 tions, or appearing as the sections of spheroidal and ovoidal nodules. The 

 distribution of mica, however, seems less profuse in the new, than in the old, red 

 clay-marl. The state of aggregation also is in general less firm in the former, 

 which is seldom wholly free from calcareous matter, and commonly effervesces 

 more or less with acids, though often very weakly : the newer marl on the 

 other hand, sometimes appears as a simple indurated clay with a conchoidal 

 firacture. In this vicinity, the new red clay-marl is best exposed at the western 

 foot of the eastward ridge, on the road from Falfield to Rockhampton, where 

 it occurs in horizontal strata. 



Masses of sulphate of strontian are frequently to be met with in this forma- 

 tion, e. g. near Wickwar, Charfield-green, and the northern brow of Tort- 

 worth hill, where a small patch of the new red clay-marl covers the zone of 

 calcareous conglomerate that surrounds that hill. They are found also in the 

 Keeper's ridge; and Dr. Cooke informs me, that in sinking a well in that ridge 

 a bed of fine white granularly-foliated gypsum was discovered *. 



* The general distribution of the sulphate of strontian in this part of the kingdom is remark- 

 able. In the preceding pages, I have more than once adverted to its appearance in the transition 

 beds. Near Bristol it has been found in the carboniferous limestone. Near Cromhall I ob- 

 served it in the slate.clay of the coal formation. Its occurrence in the calcareous conglomerate, 

 magnesian limestone, and new red clay-marl, of Gloucestershire and Somersetshire, is not at all 

 uncommon ; and in the lias limestone it is found in Aust cliff, and also near Watchtt on the 

 Somersetshire coa^t: (Geol. Trans. Vol. IV. p. 371). In the whole succession of formations, 

 therefore, from the transition beds up to the lias limestone, it appears to be wanting in the old 

 red sandstone only. 



