100 PROF. T. a. bonnet's petrological notes on the 



is nothing special to note. Some at least of the " fucoidal " markings 

 are probably Annelid -tubes ; one has^ been cut through in this slice, 

 but nothing special is shown. 



My work, I may be allowed to mention, fully confirms the opinion 

 that the quartzites of the Bunter pebble-beds of the Midland Counties 

 have been derived originally from these quartzites of l*{orth-west 

 Scotland. I have been familiar with the Bunter pebbles of Stafford- 

 shire all my life (being a native of that county), and could not sepa- 

 rate some of them from certain of the varieties which I saw in the 

 neighbourhood of Loch Maree. Further, I have recently examined 

 two of these pebbles microscopically, and find also in them occasional 

 indications of wavy-banded and cross-hatched felspars. I have 

 also identified them in conglomerates of Old Eed Sandstone and 

 Lower Carboniferous age in the more southern parts of Scotland, 

 notably in the sandstones near Brodick, Arran. 



(5) The Calcareous Series. 



Dr. Hicks* lays some stress upon the separation of the strata in 

 the bed of the stream by the gorge of Glen Laggan (" blue flags, 

 sandstones," &c.) from those seen higher up on the right bank 

 (" limestones, calcareous sandstones," &c.). It seems to me, however, 

 that it is simpler to regard them as one series, continuous with the 

 quartzites below, but much more variable in mineral character, and 

 so in the amount of change which has been produced in them. To 

 my eye they exhibited no signs of increased alteration in the neigh- 

 bourhood of the " syenite." I have examined only one specimen 

 microscopically, from the immediate neighbourhood of the latter 

 rock. It is a rather muddy-looking crystalline limestone, to some 

 extent dolomitic, as I suspect, greatly crushed and recemented, in 

 patt by infiltrated quartz. JSTo traces of organic structure can be 

 found ; and from the aspect of the slide I doubt whether such are 

 likely to have escaped obliteration, if ever they were present. 



(6) The Newer Gneiss. 



This series, as we have said, is brought into close juxtaposition 

 with the older gneiss in Glen Laggan. Here it forms a well-marked 

 escarpment, which, directly below the gorge, trends towards theS.W., 

 and passes on behind the shoulder occupied by Torridon Sandstone to 

 the mouth of Glen Docherty, forming a continuous cliff, which, on the 

 right bank of that valley, is of considerable elevation. A fault passes 

 down the bed of Glen Docherty, shifting this newer series and its 

 escarpment to the northward, so that it is exposed on the left bank 

 of the river, near Kinlochewe Lodge, and, further, by the side of the 



LoCh Broom) he traced a gradual passage from the one to the other. A fallen 

 block which I found near the commencement of the quartzite, on the right bank 

 of Loch Maree, certainly appeared, macroscopically and microscopically, inter- 

 mediate between the two ; the break, therefore, is probably rather local than 

 general. 



^ Q. J. G. S. vol. xxxiv. p. 813. 



