52 ' INTERNAL STRUCTURE. The pofition of a ftratum is determined by ob* ferving its inclination, dip, and direction. The inclination is the angle which the ftratum forms with the horizon, and is detertnined by the quadrant, “■ The dip is the point of the compafs towards which the ftratum inclines. The direSlion is % the angle which the ftratum makes with the meridian, and is determined by the compafs, It is always at right angles to the dip. 'In making obfervations of this kind, it is of the greateft importance to diftinguilh the general di rection and inclination, from the partial. To ef fect this, we muft take the refults of a number of particular obfervations, and compare them toge ther ; and thofe limilar angles which are the moft numerous, are to be confjdered as expreffive of the general inclination and direction. 3t fometimes happens, that this general pofition has alfo its va riations ; thefe muft alfo be attended to and noted, An acquaintance with the ftiape of a mountain group, will afiift us very much in fuch inveftiga- tions, as it is intimately connected with the gene ral difpofition of the ftratification of the maftes of which it is compofed. It is alfo of importance to know the fall or declivity of a mountain group, as its direction and inclination are generally con formable, particularly in the older formations, with