60 PEOF. T. G. BONNET ON THE EKBATIC [Feb. 1 896, 



tion. A fragment or two of a volcanic grit is also found, and 

 the groundmass contains a little of a carbonate. The rock re- 

 sembles some of the volcanic grits, which in Britain occur just 

 below (or, as others would say, at) the base of the Cambrian 

 system. 



(2) A rock, apparently similar to the last, but containing two or 

 three pebbles up to | inch in diameter. Two are probably a 

 reddish quartz, a third is green in colour, with colour-zoning, 

 possibly a fine-grained quartzite. 



(19) A fine-grained blackish grit, with several little flakes of mica. 

 Under the microscope it is found to be composed of angular 

 fragments of quartz, felspar, and a mudstone or phyllite, with 

 some flakes of white mica, and, more rarely, of biotite. The 

 felspar is often rather decomposed, and full of tiny flakelets of 

 colourless mica, but plagioclase can be recognized. There is a 

 good deal of a brown staining, some of which may be a hydro- 

 carbon ; possibly also a trace of a cleavage making a high 

 angle with the bedding. I cannot say more than that I should 

 conjecture the rock from its general appearance to be Palaeozoic. 



A rough vein-specimen, quartz and calcite, apparently from a ' dark 

 slaty rock.' 



(16) A very pale cream-coloured subcrystalline limestone. Under 

 the microscope it is seen to be slightly dolomitic, and composed 

 of irregularly-shaped grains, differing considerably in size. 

 Evidently it once contained rather numerous organisms, but 

 these are too much altered for exact identification. I recognize, 

 however, traces of fragments of lamellibranchs, perhaps one 

 or two small gasteropods, and several foraminifera, not impro- 

 bably representing Globigerina, Orbulina, and a Eotaline form. 

 I think the rock very likely to be Mesozoic in age. It re- 

 sembles some of the purer limestones in the Alps, where they 

 have had a sharp ' nip ' between the crystallines, and I believe 

 that it has been affected by earth-movements, followed by 

 reconsolidation. 



(6) A piece of purplish-red chert. Under the microscope clear 

 spots or veins appear in a brown-speckled ground. On ap- 

 plying the nicols, the clear constituent throughout the slide is 

 found to be chalcedonic quartz, which here and there in the 

 untinted part (where the granules run larger) shows an approach 

 to a spherulitic structure. The tinting material may be called 

 ferrite, but while some of the larger grains can be recognized 

 as brown iron-oxide, others are pyrite. In this part of the slide 

 small cylindrical bodies can be frequently identified, which, 

 though badly preserved, I believe to be sponge-spicules, and 

 there are possibly indications of other organisms. The rock 

 undoubtedly is a chert, but I cannot determine its age. 



(17) *Half of a rather large dome-shaped Favosites gothlandica 



* As I was anxious that the identification of the fossils should rest on better 

 authority than mine, I submitted the specimens marked with an asterisk to 

 E. T. Newton, Esq., F.K.S., who has kindly named and commented on them.— 

 T. G. B. 



