1869 Sawkins "Reports on the Geology of Jamaica";
writing of St Ann
" From the base of the ridge to the Moneague the valley is comparatively level, and covered
with a considerable depth of red ferruginous earth, and highly cultivated in guinea grass. From the Moneague to Blue Hole
at Rio Hoe there is a considerable descent; and the lower beds of the white limestone and a portion of the yellow limestone
appears in the vicinity of Walton. There is also considerable deposit of alluvium
extending from Blue Hole to Walton, which appears to lie on the yellow limestone, as fragments of the latter are found on
the borders of the lake containing orbitolites and other fossils that are only found in the yellow limestone.
At Blue Hole there is a spring of water that rises from below the
white or yellow limestone, which is now covered with calcsinter or calctuff; the depth from which this water rises produces
a light blue colour, hence the name. The water from this source makes tortuous
windings over an alluvium more than two miles in extent, and then disappears below a ledge of limestone on the western extremity
of the lake. This lake in the fall of the year 1863 expanded its dimensions more
than it had for many years before; and as considerable time elapsed between the season of the periodical rains and the augmentation
of the water in the lake, it would therefore appear to be supplied from a subterranean reservoir, the channel of which is
subject to obstructions. Since 1804 it does not appear to have reached the extreme
outer bank until 1863. To the north-east of the Blue Hole there is another but
smaller lake, which evaporates during the dry seasons, and leaves a white calcareous deposit over the surface."
