The prevalence of crystalline, concretionary and drusy structures in dolomite can thus be simply explained.
He pronounces it "a superficial highly ferrugineous sandstone, with concretionary veins and aggregations."
A sort of concretionary affinity comes into play, and the different chemical units congregate together.
In deposits of this nature in South America these concretionary masses form distinct beds.
Some shew a flaky or laminated structure; others are concretionary.
Kankar or ghutin (concretionary carbonate of lime) is collected for this purpose from the river-beds and alluvial deposits.
Its formation is consequently the result of “concretionary action.”
At Tusayan the builders have utilized stone of a concretionary formation for roof drains.
These examples will indicate the great variety of substances which may give rise to concretionary structures.
The mineral is occasionally found as concretionary masses (sphaerosiderite) in cavities in basic igneous rocks such as dolerite.