Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/172



The whole series presents from one end to the other a repetition of the same parts, although the several substances are in different places differently proportioned, the one exceeding in one place, while in another a different member of the series will be found predominant. One exception to this rule will afterwards be noticed.

The rocks which compose the series are the following.

Red sandstone, more or less indurated, of which the general characters were formerly described.

Quartz rock, or, as some may prefer to name it, indurated sandstone, passing from lead blue to grey and brown, sometimes pure, at others containing felspar.

Schist, which is sometimes not to be distinguished from ordinary clay slate, and at other times contains particles of quartz and mica. If one term is to be used for the whole it must probably be called graywacké schist.

White compact quartz rock: this substance is found only in one part of the series.

In the original paper I described the red sandstone as following the blue rock and schist in conformable order, which it in fact does throughout a considerable tract without any repetition of the two latter. But on pursuing these beds further than I then did, whether backwards or forwards, according to their relative inferiority or superiority, repeated alternations of all those substances occur.

The dip which I also described as constant and westerly, is only thus regular from that part of Loch Eishort whence my examination at that time commenced, to its upper portions, ascending according to the order of the beds. In tracing from that point towards the last, or downwards according to the order of the beds, through those parts of the country respecting which I formerly