768 GEOLOGY. 



a group of the animalcules, being cylindrical, either simple or branched ; Madrepora, 

 character arborescent or frondescent ; and Meandrina, character either turbinated 

 or globular, the surface more or less confluent, but marked with sinuous ridges and 

 valleys. We have had occasion repeatedly to notice corals in the more ancient strata of 

 the globe, especially in the Silurian rocks, evidencing the existence, in far remote ages, 

 of kindred forms of vitality to those that now inhabit the ocean ; but their geographical 

 range was then more extended than at present. Now it is tropical ; but then it reached 

 to high latitudes, intimating the higher temperature of the northern seas, and the general 

 prevalence of a warm climate, in the earlier stages of our planet's history. 



Caryophyllia fastigiata. Madrepora muricata. Meandrina labyrinthica. 



Peat-mosses or bogs are organic products, consisting of vegetable matter spread over 

 extensive areas in northern latitudes ; for in tropical climates, except on high lands, the 

 decomposition of vegetable substances proceeds so rapidly, that they are resolved into 

 their ultimate elements before peat can be produced, or they are removed by insects. 

 Accordingly, formations of this kind are limited -chiefly to the colder regions of the globe. 

 They are usually found in level situations, or on declivities abounding with springs, 

 where varieties of plants. are nourished, the decay of which produces a spongy vegetable 

 mould, to which fresh contributions are annually made from the annual decay of new 

 races. A morass, yielding and quivering to the tread, is the first product. This often 

 becomes a firm deposit, as the accumulation increases, or when, from accidental causes, 

 the mass is drained, or the supply of water ceases ; but frequently the upper part is hard, 

 yet trembling, arising from the slight consistency of the substratum. These are called 

 moving-bogs in Ireland, and quaking-mosses in Scotland, and are frequently perilous to 

 travellers and cattle. Gilpin describes the Solway moss a flat area, about seven miles 

 in circumference, on the confines of England and Scotland as covered with grass and 

 rushes, presenting a dry crust and fair appearance, but shaking under the least pressure, 

 the bottom being unsound and semi-fluid. He states that the adventurous passenger, 

 who sometimes in dry seasons passes this perilous waste to save a few miles, picks his 

 cautious way over the rushy tussocks as they appear before him, for here the soil is 

 firmest ; but if his foot slip, or if he venture to desert this mark 6f security, it is possible 

 he may never more be heard of. At the battle of Solway, in the time of Henry VIII. 

 12), when the Scotch army, commanded by Oliver Sinclair, was routed, an unfortunate 

 troop of horse, driven by their fears, plunged into this morass, which instantly closed 

 upon them. The tale was traditional, but it is now authenticated, a man and horse in 

 unplete armour having been found by peat-diggers in the place where it was always 

 supposed the affair had happened. The skeleton of each was well preserved, and the 

 different parts of the armour easily distinguished." 



