460 Br. Irving — The Malvern Crystallines. 



This is "uniformity" indeed, but quite a different tiling from the 

 *' uniformitarianism " of the Hutton-Lyell school.] 



(b.) Sericite- schists. — The writer has adopted this term from a 

 letter written to him by Dr. Callaway for the satiny, distinctly- 

 foliated, and contorted rock, which is exposed on the western side 

 of the larger quarry at Raggedstone, and is unconformably overlain 

 by the Hollybush Sandstone. He has seen nothing like it in any 

 other part of the Malvern Hills. It is something more than a 

 phyllite, and reminds one of nothing so much as the Casanna and 

 other younger schists of the Alps. It appears to be a fragment of 

 the lithosphere belonging to a much later Archaaan stage of develop- 

 ment than the rest of the Malvern Chain, a stage of development in 

 which super-heated water or steam has played a prominent part, 

 rather than to the pyrogenic stage of rock-genesis,^ to which most 

 of the rocks of the Malvern Chain may be referred. The writer 

 failed in his attempt to trace a gradual transition from them into the 

 gneissose rocks adjoining these schists. 



Taking into account the great discordancy that exists between 

 these schists and the overlying Upper Cambrian strata, it appears 

 easier to look upon them as the sole i-emnant (now exposed to view) 

 of the younger Archasans left by the extensive denudation to which 

 the whole region must have been subjected in early Cambrian and 

 later pre-Cambrian times, rather than as having been " manufactured " 

 simply by those dynamic agencies, through the instrumentality of 

 which tlie earlier mountain-building movements of the Malvern 

 region were effected, though probably somewhat modified by them. 



(c.) Micaceous phyllolithie roeks. — An alleged case of conversion 

 of a felsite into a "mica-schist" in the Raggedstone has been described 

 by Dr. Callaway. The writer has observed something of the sort 

 in some of the quartzo-felspathic veins, which are so well-developed 

 in the old quarries at Wind's Point and Little Malvern (near the 

 Roman Catholic Chapel), that they have been instanced over and 

 over again, by writers on the geology of the district, as clear cases 

 of truly-bedded sedimentai'ies ; though a closer examination of them, 

 in the light of experience gained in other parts of the range, makes 

 it far more probable that they are deformed crystallines, rather 

 than worked-up clastic materials. Some of these more felspathio 

 individual veins have acquired a structure (a cleavage-foliation) 

 approaching and simulating true schistosity, becoming easily fissile 

 under the hammer, with white mica plainly developed macro- 

 scopically on their planes of cleavage. This, no doubt, is a secondary 

 product due to the action of infiltrating water, and formed at the 

 expense of the felspar ; but it is difiScuIt to see why such a rock 

 should be designated a schist {strirto sensn) any more than some 

 laminated sandstones of Mesozoic age, on the lamination-planes of 

 which a similar deposit of secondary mica has taken place. Call 

 them what you will, they are certainly very different things from 

 the older mica-schists of the Alps, in which we meet with well- 



' Compare " Metamorpliism of Eocks," p. 91, where the distinction here implied 

 is clearly drawn. 



