English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Very few persons associate volcanoes with the fiat land of the Gulf Coastal Plain of southwestern Arkan­ sas, but for a number·of years geologists have known that the "roots" of old volcanoes were present near Murfreesboro, in Pike County. They found here not ,only the rocks that ~nce composed the craters of these volcanoes, but also the decomposed material filling their necks, which carries diamonds and is almost identical with the diamond-bearing earth of the great Kimberley Inine of South Africa. Much of the material ejected by these volcanoes was in the form of volcanic ash, sand, nnd lapilli, which were thrown out by vio­ .lent explosions and then widely distributed by wind and water. , The present paper deals with these and other vol­ 'canoes in Arkansas and with recent ·discoveries of material tha,t was ejected from them. From the char­ acter of this lnaterial it has been possible to determine the geologic period in which the explosions occurred, the localities in Arkansas whence the material came, nnd the agencies by which it was distributed.

Water-laid volcanic rocks of early Upper Cretaceous age in southwestern Arkansas, southeastern Oklahoma, and northeastern Texas