E. S. Dana — Petrography of the Sandwich Inlands. 453 



Through the kindness of Mr. Baker, the writer has received 

 an admirable series of them, part of which are shown, one- 

 third of the natural size, in the accompanying plate. These 

 specimens were collected with great care and skilfully packed 

 in moss and although fractured at many points when they ar- 

 rived in New Haven, and thus divided into sections an inch 

 or two in length, it was found possible to cement them to- 

 gether in their original positions.* 



The general aspect of the stalactites and stalagmites is so 

 well shown in the series of figures on plate XIY that 

 but little description is needed. It will be noticed that while 

 some are straight and nearly uniform, others are curiously 

 gnarled and knotted, especially near their lower extremities. 

 The end has often a little process thrown off at right angles, 

 a little hook, or a close spiral of two or three turns often tan- 

 gled or knotted together. The simple rods are usually round, 

 not often flattened except when there is a sudden change in 

 direction, when they may be pinched together like a glass 

 tube bent when hot. The surface is exquisitely ornamented 

 with most delicate markings. The stalagmites, formed by the 

 droppings from above, are intricate clusters or piles of simple 

 drops several inches in height as well represented in figures 

 a and b on the plate. 



The exterior of the stalactites has usually a more or less bright 

 metallic luster, and, though sometimes dull and fine granular, 

 the surface often reflects the light brilliantly from a multitude 

 of crystalline facets ; these sometimes separate into distinct 

 scales, shown to be largely hematite by their reddish streak, 

 though magnetite is also present. Minute rounded crystals, ap- 

 parently also of hematite, are sprinkled often thickly over the 

 surface. Sometimes the metallic covering is very thin, or is 

 not continuous, forming patches on a brown surface. Oc- 

 casionally at the ends it is altogether absent, and the exterior 

 is thus brown and glassy in aspect, but still retains the poly- 

 hedral crystalline aspect; this glass-like crust polarizes light 

 and is probably augite. Over portions of the rods — and in 

 the case of the straight uniform ones (see the plate) over the 

 whole length — the surface is transversely ribbed or corded in 

 the most delicate manner. The beauty and perfection of these 

 little ripplemarks, as seen under a hand-glass, are beyond de- 

 scription or adequate representation. They are parallel and 

 symmetrical for a limited distance, but vary in fineness and form 

 with every change in direction of the stalactite itself. Their 

 flow is especially varied about each little projecting knob. 



* For this skillful work as well as for the drawing of the plate, and of figs. 1-4 

 and 7, the writer is indebted to Dr. E. H. Barbour, recently of Tale University. 



