On the Origin of Septarian Structure

W. Alfred Richardson
Lecturer in Civil Engineering, University College, Nottingham

Summary: In this paper an endeavour has been made to establish the following points: That septarian structure consists of a polygonal system of cracks corresponding to a mud desiccation structure. That the cracking of the nodule is due to the desiccation of a colloidal centre by chemical means. That the nodules originated by the rhythmic precipitation of solutions diffusing through a colloid according to Liesegang's laws.

Finally, in addition to acknowledgements made in the text, I beg leave to thank Professors H. H. Swinnerton and C. H. Bulleid for help-ful criticism; Mr. H. Preston for placing his collection at my disposal; the chemical staff of University College, Nottingbam, for generous assistance; and Dr. G. T. Prior for his kind attention at the British Museum.

Mineralogical Magazine; May 1919 v. 18; no. 86; p. 327-338; DOI: 10.1180/minmag.1919.018.86.04
© 1919, The Mineralogical Society
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