Report on Erratics from Stonar, Kent
Fifteen samples of erratics from the shingle deposit at Stonar, Kent, submitted by Mr. W. P. D. Stebbing, have now been examined, and Dr. J. V. Harrison, to whom I am most grateful, has helped greatly in the following description. The numbers of the samples refer to those given to them by their finder.
[pg51]refractive index is less than that of Canada Balsam. It is frequently spherulitic. No quartz was seen in the slide. Biotite is both porphyritic and scattered through the groundmass, and sometimes shows alteration to chlorite, and to magnetite. Accessory zircon occurs.
[pg52]Most of the rocks in this collection resemble types known in the Drift of East Anglia, but the latter have not yet been worked out in sufficient detail to say definitely whether these Stonar erratics might have come from there. It should be pointed out that in any case they may also have been derived from the Thames Plateau and River Gravels, but it would not be easy to distinguish between the Thames erratics and those of East Anglia, because in some cases these two groups have been derived from a common source.