On recent Depression in the Land

Abstract

The human period may be subdivided into the present, or that in which geological events are subjected to our own observation; the historieal, or that in which they have been observed and recorded; stud the antiquarian, in which, although we cannot assign a date to them, we can prove from human remains or works of art that they must have taken place since the earth was inhabited by man. Having recently observed proofs of movements of depression in each of these periods, I proceed to notice them in their retrograde order. When I visited Pozzuoli in 1819, the floor of the temple of Serapis was dry, but I remarked that the channels cut across it for the purpose of draining the waters of the thermal spring which rises within i t s predncts were nearly filled with sea-water, with a sensible current flowing inwards, or from the sea ; when I returned in 1845, I found that the high-water mark stood at 28 inches above the pavement, exhibiting a rise of about an inch yearly. As there is a rise and fall of tide of nearly 10 inches within the building, and as I have no means of knowing the state of the tide at my first visit, I cannot speak with certainty as to the exact change of level which had taken place during the interval between my observations ; I am however satisfied that it could not be much more or less than one inch yearly. Professor Forbes