Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/171

 there will be found a transition, unexpected and improbable as it may at first seem, between the two series, that of the gneiss, and that of the graywacké and sandstone which follows it; but at what point between the two extremities of the gneiss boundary a decided change takes the place of a gradual transition it will be for ever impossible satisfactorily to determine. I must add that the limit of the gneiss series on the eastern side of Sleat is the sea shore itself.

I must now proceed, before entering further on the transition of the gneiss series, to describe that which in the original paper I called the series of blue quartz rock and schist, in which there is somewhat to amend and somewhat to supply. With this I must here include the red sandstone, formerly separated from the other two rocks on the same systematical views which led into the other errors already mentioned. The conclusions then drawn were sufficiently justified by the partial view of the country which I had at that time obtained, but they were founded on observations too limited. A more complete investigation, with a greater disregard of theoretic views, would not only have led to sounder conclusions, but have removed many difficulties which I encountered both in the examination and in the attempt to reconcile discordant phenomena.

Although on reviewing the places I examined before, I find the description formerly given of these substances locally correct, and the conjecture I had formed of the nature of the rocks toward the Kyle ri'ch equally so, yet an examination of additional parts of this series renders it necessary to remodel the whole description, as it possesses a degree of intricacy which it was impossible to suspect, and which nothing but a very accurate examination could ever have induced me to credit, since it is at variance with the usual phenomena that attend these rocks.