Black Friday Offer – Save 25% off all imagery use code: ALAMYBF25

Report of a reconnaissance from Carroll, Montana Territory, on the upper Missouri, to the Yellowstone National Park, and return, made in the summer of 1875 . achyte, with acubical fracture breaking into large angular blocks, in striking contrast with the loose slabs of theother trachyte which cover the slopes of Cone Butte. This is probably a later dike, subsequent tothe formation of the other hills. This trachyte, as well as that of Cone Butte, was found in frag-ments abundantly over the prairie, even to a distance of fifteen miles from the mountains. It ischaracterized by large crystals of a

Report of a reconnaissance from Carroll, Montana Territory, on the upper Missouri, to the Yellowstone National Park, and return, made in the summer of 1875 . achyte, with acubical fracture breaking into large angular blocks, in striking contrast with the loose slabs of theother trachyte which cover the slopes of Cone Butte. This is probably a later dike, subsequent tothe formation of the other hills. This trachyte, as well as that of Cone Butte, was found in frag-ments abundantly over the prairie, even to a distance of fifteen miles from the mountains. It ischaracterized by large crystals of a Stock Photo
Preview

Image details

Contributor:

The Reading Room / Alamy Stock Photo

Image ID:

2AJCH6G

File size:

7.2 MB (561.9 KB Compressed download)

Releases:

Model - no | Property - noDo I need a release?

Dimensions:

2313 x 1081 px | 39.2 x 18.3 cm | 15.4 x 7.2 inches | 150dpi

More information:

This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright. Alamy charges you a fee for access to the high resolution copy of the image.

This image could have imperfections as it’s either historical or reportage.

Report of a reconnaissance from Carroll, Montana Territory, on the upper Missouri, to the Yellowstone National Park, and return, made in the summer of 1875 . achyte, with acubical fracture breaking into large angular blocks, in striking contrast with the loose slabs of theother trachyte which cover the slopes of Cone Butte. This is probably a later dike, subsequent tothe formation of the other hills. This trachyte, as well as that of Cone Butte, was found in frag-ments abundantly over the prairie, even to a distance of fifteen miles from the mountains. It ischaracterized by large crystals of a glassy orthoclase, which give it a porphyritic structure. Underthe microscope, these crystals are found to be more or less clouded, in consequence of incipientalteration: this is also shown by the indistinct colors obtained in polarized light. Accompanyingthe large crystals of orthoclase are smaller thin-bladed crystals in large numbers. The other essen-tial constituent is the hornblende, which is seen in simple distinct prisms: it has a deep-greencolor, and is strongly dichroic. No quartz was observed. The most interesting feature of the rock FiK.7.. is the green base, which, under a low magnifying power, seems to be without structure, but, whenmagnified highly, is resolved into countless minute, acicular crystals, jumbled together in a con-14 w 106 KEOONNAISSANCB FEOM CARKOLL, MONTANA, fused mass. They show very little color in polarized light. They may be zeolitic; but a chemicalanalysis, which the circumstances do not now admit of, would be required to settle the point. In the ravine spoken of, 355 feet below the summit of Cone Butte, we were surprised to find aseries of slates and sandstones. The cut (Fig. 7) will give some idea of the relations of the rocks, it being a sketch taken from a point below to the west. The total width of the gap is about 70yards; the trachyte rising abruptly on both sides. The trachyte of the hill to the south is quitesimilar to that of Cone Bu

Save up to 70% with our image packs

Pre-pay for multiple images and download on demand.

View discounts

Search stock photos by tags