436 
BEDDED GRANITE, MIASCITE AND MINERALS OF MIASK. 
the ph8enomenon is due to the manner in which the igneous matter flowed, cooled 
and became solidified 1 . Whatever, therefore, may be the mineral distinctions in the 
granitiform rocks which compose the western slopes of the Ilmen Hills near Miask, 
and however much they may have a stratified character, we believe that they are all 
of igneous origin. But why should we not meet with granite as regularly strati- 
fied as the greenstone and basalt of former epochs, or as the lava of modern times, 
all of which are common phenomena? In illustrating the borders of England and 
Wales, or the region of Siluria, we have, indeed, ourselves described several tracts 
(Llandrindod in Radnorshire, and Shelve in Shropshire, &c.) where thin-bedded 
crystalline rocks, having a true igneous matrix, not only alternate conformably 
with ordinary sedimentary strata, but have even enveloped the marine remains of 
the period 2 . The largest portion of North Wales, as Professor Sedgwick has so w^ell 
shown 3 4 , is, indeed, made up of such alternations, on a very grand scale, of Lower 
Silurian strata with porphyries. Beds similar to the “ schaalstein ” of the Lahn 
in Nassau, which prevail in several places along the eastern flank of the Ural, are, 
in fact, but one of the terms in a series of igneously-formed strata, which are linked 
on to sedimentary deposits, whilst their opposite extreme is developed in the flaglike 
granites and syenites of which w r e are here speaking. These rocks are succeeded 
on the east by great masses of granite, which have usurped so large a portion of the 
surface in the adjacent parts of Siberia, and of whose extension to the south we 
shall speak hereafter. 
e do not piofess to entei upon a description of the many beautiful and curious 
minerals, now well-known to collectors, which have been obtained from these hills 
of Miask, but referring to the work of M. G. Rose, we will merely announce, that 
all the finest of these (zircon, black mica in large plates, green felspar in enor- 
mous crystals, albite, elaolite, sodalite, cancrinite, apatite, ilmenite, titanium of 
iron, pyrochlore, hornblende, beryl, topaz, garnet, &c.) are found either in beds, 
veins, or nests of the granitic ridge of the Ilmen. Masses of the rock with which 
some of the above minerals were associated, and which dip south-west from the 
sides of the greater Ilmen, and which appeared to us nothing more than flaglike 
1 See Humboldt’s description of these granites, Asie Centrale, vol. i. p. 295 et seq., and Relat. Histo- 
rique, t. xi. pp.58, 84, 99 and 405 ; t. iii. p. 250. Dr. M'Oulloch has also described certain granites of 
Aberdeenshire as apparently stratified, though he viewed them only as “ examples of laminar disposition.” 
(Syst. of Geo!., vol. ii. p. 94.) 
4 Silurian System, pp. 269, 325 et seq. 3 Proc. Geol. Soe., vol. iii. 
