Seamed Structure. 57 culators building on thefe errors have reprefented the whole cruft of the globe as an irregular and unfeemly mafs. It is indeed furprifing, that men poffefled of any knowledge of the beautiful'har mony that prevails in the ftrudure of organic be ings could for a moment believe it poffible, that the great fabric of the globe itfelf,—that magni ficent difplay of Omnipotence,—fhould be defti- tute of all regularity in its ftru&ure, and be no thing more than a heap of ruins. 36. Seamed StruSturc.—This ftrudure is form ed in thofe cafes where there are feams which are parallel in one direaion, but interfea each other in another. The moft ftriking example of it is the columnar. The columns are fometimes regular, fometimes approach to the globular form, and occur even curvated. They are from a few inches to many fathoms long, the length being de termined by the diredion of the feams in one di reaion. In the iflands of Staffa and Eigg there ' are admirable examples of this kind of ftruaure. Thefe columns are fometimes colleded into groups, and fuch groups are often feparated from each other by feams or rather rents, which render them more diftina. Such groups may be confidered as immenfe diftina concretions. The columns of fuch a group often tend towards a centre, others are parallel or perpendicular, fome are horizontal \ and all this variety fometimes occurs in the fame Vol. III. ' H hilL
