During a stay of nearly six weeks, made last July and August, at the Lizard, Cornwall, I had ample opportunity of correcting former, and making some fresh observations.

With regard to the first of these, and to some of the strictures recently passed on them, I found that I had little or nothing to regret as to what I had already written on the subject, with the exception of the “felsitic-like-rock” at Housel Cove, which I should now rather regard as a mass segregated, or separated out of the common magma, common magma, than as an altered portion of the hornblende-schist as I then described it—my object at the time being to show that it was not a dyke; a view I am still convinced of. I now pass on to recent observations.

Prof. Blake, F.G.S., President of the Geologists' Association, has been good enough to send me cuttings from his recently published work “Annals of British Geology” containing his running comments on papers by me published during the period embraced by his volume, and for which I desire to tender him my best thanks.

I think it will be more courteous on my part to offer a few observations by way of reply to Prof. Blake's criticisms than to allow them to pass in silence; but I must confine myself to one paper, by way of sample.

Prof. Blake's book is a valuable work of reference; but the criticisms appear to be both hurried and inaccurate. In the notice of my Monograph the title is incorrectly given: there are certain other clerical errors; and some mistakes which a little more investigation would have prevented.

While placing his comments in brackets, it is unfortunate that Prof. Blake has not found some means to distinguish between remarks based upon the author's words, and statements of his own. This is especially noticeable in the “critical digest” of Haugia, where remarks, which appear as if they originated with Prof. Blake, are really my statements in another form.

The commonly accepted theory of the origin of granite is that, in view of indications that it had been subjected to great pressure, it was formed deep in the earth's crust in a molten state, and, after consolidating, thrust up through it, or exposed at the surface by denudation. This theory is not altogether satisfactory, being equivalent to an assertion that a stately building was first constructed and its foundation laid afterwards. Like some other unsatisfactory theories, it has been so often reiterated that it is tacitly assented to as authoritative, on the principle, we suppose, that what everybody says must be true. There are existing conditions analogous to those under which the trappean rocks were formed, as illustrated by modern submarine and subaërial erupted rocks; but the conditions under which primitive granite originated are not now represented in any part of the world.