The isolated rocks of the coral formation, which are found lying on the summit and declivity of hills in the Scotland district, remain to be considered. Their size is considerable, sometimes as much as from twelve to fifteen feet in height, never rounded, but ahvnys angular, and of the sanle character as the cliffs of coral-rocks. They lie generally half-buried in the ground, with their edges upturned, and as if tossed there by force. A lthough the cliffs of the coralline forlnatioll exceed in height (excepting l\fount Hillaby) the hills in Scotland, the intervening valleys do not allow us to suppose that these masses of coral rock were detached from these cliffs, and, falling do\vn the Inountains, rolled up again to their present situation, traversing valleys and ascending acclivities before they perched upon the top of distant hills. I conjectured that the coralline crust nlight have once extended over the Scotland district, and that the volcanic force which produced the upheaval of the Scotland strata, might have burst the crust and hurled it partly into the depths of the sea, and partly upon the sides of the hills and their sutnmits. The immense seawave which is known to accompany shocks of earthquakes, and commits great havoc along the coasts subjected to it, might in this instance have carried on retiring the greater portion of the coralline crust away, and left only a few as a remnant. It has been considered by others, that a similar agency as that \vhich transported the gigantic boulders of the north of England and Germany has like\"ise operatcd here. I think it however probable, upon a reconsideration of DIy own supposition, that thcsc Inasses have been detached fronl the cliffs which no\v border the Scotland district, previous to the upheaval of thc marine bottom, and ~ul1k on the submarine inequalit.ics.