214 R. H. Rastall — Minerals of Lower Greensand. 



some individuals being as much as 03 mm. in length, though most 

 are smaller. Many of them show very fine examples of the spherical 

 and tube-like inclusions described by the above-mentioned author. 

 Apart from these the substance is usually quite clear, and zoned and 

 coloured forms are exceedingly rare. The larger crystals are 

 generally quite sharp, but many of the smaller ones are much 

 rounded. 



The hornblende is mostly in the form of rounded and rolled grains, 

 or as much rounded as this mineral is capable of becoming owing to 

 its good prismatic cleavage. The colour is greenish blue, with 

 strong pleochroism, and the mineral is undoubtedly a variety rich in 

 soda, approaching arfredsonite in composition ; it may have come 

 from Scandinavia. 



Fig. 1. — Kyanite, Sandringham Sands, x 60. 



The most interesting feature of these specimens is the presence of 

 a considerable amount of garnet, a mineral conspicuously absent from 

 most localities. It occurs both in angular chips and in well-rounded 

 grains, the former being distinctly the larger, and includes both 

 brownish-pink aud colourless varieties. The significance of the 

 occurrence of garnet in Norfolk will be dealt with later. 



2. Sandringham: Sands, Castle Rising, Norfolk. 



These specimens were taken some years ago from a sand-pit near 

 Castle Rising, on the west side of the high road from Kings Lynn to 

 Hunstanton. The sand, which is quite loose and incoherent, is pale 

 grey in colour, evidently containing very little iron. A considerable 

 amount of black carbonaceous vegetable material, probably decayed 

 roots, is present. A slide of heavy materials prepared from this 

 sample (No. 10641 in the Sedgwick Museum Collection) was figured 

 by Dr. Hatch and the present author. 1 



The slide has been again carefully examined. The principal 

 minerals found were kyanite, tourmaline, staurolite, rutile, with a 

 small proportion of zircon and green biotite. The characteristic and 

 dominant minerals are kyanite and tourmaline, which are both 

 unusually large and well developed. 



1 Hatch & Rastall, The Petrology of the Sedimentary Rocks, London, 1913, 

 p. 44, fig. 5. 



