PEECARBONEFEEOUS ROCKS OF CHARNWOOD FOREST. 347 



series. The resemblance of the breccias in the upper part of the hill 

 to those of Cadman has already been noticed. 



Ee this as it may, the rocks of Bardon Hill, as a whole, have a 

 marked resemblance, especially under the microscope, to the group 

 described in the last section ; thus it is very probable that this 

 Sharpley- Cadman series, in an attenuated condition, reappears here 

 on the other side of a synclinal, which most likely is more or less 

 broken by faults. 



(5) Fragments in Agglomerates. 



A few fragments from the agglomerates have already been de- 

 scribed in Part II. ; but in the hope of throwing light on the structure 

 of the Sharpley rock and obtaining hints for conclusions, ten care- 

 fully selected fragments have been subsequently examined micro- 

 scopically. They are from the following localities : — Eatchet 

 HiU (2), Gunhill (1), High Towers (4), Timberwood Hill (1), near 

 Whitwick school-house (1), Whitwick Parish Quarry (1). The speci- 

 mens from Eatchet Hill have a minutely cryptocrystalline ground- 

 mass with scattered crystals of quartz, felspar, magnetite and secon- 

 dary epidote. The first two minerals resemble those in the Sharpley 

 rock ; and there is much similarity in the ground-mass. One of the 

 High-Towers specimens (from an agglomerate nearly opposite to the 

 lodge) shows a faintly mottled structure, which is rendered more 

 distinct by a marked difference of colour on applying a selenite 

 plate. Probably it is the remains of a structure similar to those 

 figured by Zirkel in plates vi. and viii. of his " Microscopical Petro- 

 graphy " (U.S. Geol. Explor.). We find also that the mottled pink 

 and green fragments, somewhat like syenites in macroscopic structure, 

 differ but little from the purple fragments. The ground-mass is 

 eryptocrj^staUine, and in this particular specimen shows fairly distinct 

 traces of a fluidal structure. The others call for no special note. 

 The microliths in the Whitwick School-house fragments (rather de- 

 composed) are more acicular than in the others; that from the A^Hiit- 

 wick Quarry (also rather decomposed in parts) exhibits distinctly an 

 irregular fluidal structure. In our former notice (vol. xxxiv. p. 208) 

 we doubted whether two specimens from the last locality were 

 igneous; having in the interval enjoyed many opportunities of studying 

 both the older trachytic rocks and the " hallefliuta " group generally, 

 we have now no hesitation in recognizing all as igneous. The 

 structure then described is analogous to that mentioned above in one 

 of the High-Towers specimens. 



These fragments also, allowing for decomposition and the formation 

 of some secondary minerals, present very considerable resemblance 

 to many rhyolitic rocks of much more recent date, such as those of 

 Hungary ; it is even possible that an undevitrified base may oc- 

 casionally remain. Their structures are hardly distinctive enough 

 to throw much light upon correlation. The Gunhill and Whitwick 

 School-house specimens, which difier more from the ordinary type, 

 are most alike ; but it is quite possible for all to belong to the same 

 general series. Pield evidence inclines us now to regard the Gun- 



