Terrible as was this outbreak, the explosive violence was not so great as of the eruption from some unknown vent whose deposits are about Quiché in Guatemala, in the valley of the Chixoy, and elsewhere; and Pacaya has in some prehistoric time thrown out sand and pumice in greater quantity than did Coseguina, as we see by the deposits about the Lago de Amatitlan. [Illustration: Lago de Ilopango, 1880.] With the mention of the Lago de Amatitlan it occurs to me that the so-called volcanic lakes of Central America deserve a short notice. I would not claim that there are not here genuine pit-craters filled with water and called _lagos_ or _lagunas_. On the summit of many of the extinct volcanoes are craters filled with water, as Ipala and others, and as Agua was before the destruction of the crater-lip in 1541; while in San Salvador and Nicaragua are many lakes, usually of small extent, but sometimes so large as to mislead the casual observer as to their origin, though of undoubtedly volcanic nature. Of this last class is the Lago de Masaya, from whose deep pool the people of the neighboring village obtain all their water. Coatepeque is another volcanic lake, whose walls are so steep that they can be descended only at certain points by means of ladders and steps cut in the lava rock. Finally there are many pits, sometimes no more than a hundred feet in diameter, but of very great depth, and filled sometimes with fresh water, but more commonly with saline waters so strongly impregnated as to be undrinkable. The great lakes of Amatitlan and Atitlan are not certainly volcanic, although their shores are dotted with hot-springs and guarded by volcanoes,—they are not, that is, actual craters; but the former seems to be the result of a subsidence caused perhaps by the removal of material from lower layers by eruptions of Pacaya, and it is of no considerable depth, while good authority has considered the Lago de Atitlan the result of damming up a valley and streams by the masses of the volcanic group of the same name. A glance at the map of this lake (p. 154) as given by the French geologists whose opinion is quoted, will show that the volcanoes occupy a position not far from the geometrical centre of the Lago, or where they should be if the lake was an ancient crater. Compare with this, if you will, the plan of an undoubted volcanic lake, that of Ilopango in San Salvador. This body of water is not only the seat of volcanic eruptions, as is also the Great Lake of Nicaragua, but probably fills a depression that has been the result of the coalescence of several points of eruption. I have before me the interesting report to the Guatemaltecan Government by my friend Edwin Rockstroh of his observations made on the eruption of one of these craters in 1880. The lake is 9,200 metres wide from east to west, and 7,300 metres from north to south, with an area of 54.3 kilometres. Completely surrounded by precipitous