Report on the geology of the state of Maine . so observed to rest upon strata of flintyslate, which evidently owes its induration to the action of 14 TOPOGRAPHICAL GEOLOGY* the superincumbent rock. Of this, however, we shall treatmore fully hereafter. At Broad Cove on the southern part of Moose Island weobserved a large mass of stratified slate, impregnated with asmall proportion of carbonate of lime, included betweenhigh walls of trap-rocks, and exhibiting remarkable contor-tions in its strata, as if they had been broken up and elevatedby subterranean power. This slate has a general inclinati
Report on the geology of the state of Maine . so observed to rest upon strata of flintyslate, which evidently owes its induration to the action of 14 TOPOGRAPHICAL GEOLOGY* the superincumbent rock. Of this, however, we shall treatmore fully hereafter. At Broad Cove on the southern part of Moose Island weobserved a large mass of stratified slate, impregnated with asmall proportion of carbonate of lime, included betweenhigh walls of trap-rocks, and exhibiting remarkable contor-tions in its strata, as if they had been broken up and elevatedby subterranean power. This slate has a general inclinationto the S. W.; but owing to the confusion in its strata, theangle of the dip could not be estimated. This slate is filledwith abundant impressions of marine shells, resembling thegenera mytilus, tellina and lingula; but no remains of thesubstance of the shells could be found, it having beenentirely absorbed by the rock. The following diagramexhibits the situation of the rocks at Broad Cove. Theprecipice is 60 feet above the waters edge. a b. a a Greenstone trap-rocks. b Contorted strata of slate containing impressions of marine shells. A few narrow veins of the sulphurets of lead and copper, andarsenical iron are found in the trap-rocks on Moose Island,but they are too insignificant to be of commercial the greenstone trap-rock of Eastport is extremelyhard and slow of disintegration, it forms, when decomposed,an excellent soil, which covers the rocks with a thin, butfertile stratum of a dark brown loam, in which the usualculinary vegetables grow luxuriantly. This soil is remarka-ble for the excellent potatoes which it produces and whichvie with those of Nova-Scotia. Where this soil containsany sensible proportion of sulphate of iron or copperas, it TOPOGRAPHICAL GEOLOGY. J 5 may be amended by the use of lime, which will change thedeleterious salt into a valuable stimulant to vegetation. From Eastport we made an excursion by land to Perry,tracing the extent of the
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Keywords: ., bookcentury1800, booksubjectgeology, booksubjectminesandmineralr
