180 REV. E. HILL ON THE MATRIX OF [May 1902, 
granules are found in samples from Ely, Horringer (1 mile south- 
west of Bury), and Stort Hill near Bishops Stortford. Samples from 
Pakefield (south of Lowestoft), Thorley and Hockerill (near Bishops. 
Stortford), and, as above mentioned, from the Boston dredgings and 
the pit south-east of Saxmundham, contain granules of other kinds 
or none. Now, if these localities be laid down on a map, it will be 
found that all those from which come granules of the grey clay or 
limestone lie within a certain area, and the rest outside it. The 
washed residues which yield those granules are, to the eye, all grey 
powders ; the original clays are all dark (sometimes called blue) ;. 
they are so like each other in hand-specimens, that samples from. 
different places are often indistinguishable. Presenting so many 
common features, and occupying a definite district, they must be 
classed together as one. 
The clays, the washed residues of which do not yield granules of 
this kind, are red, yellow, or grey, and their residues red, yellow, or 
whitish. Some are probably samples of the first kind altered ; the 
alteration, however, has not removed the fragments of chalk. At 
several of the localities— Pakefield, the pit south-east of Saxmundham,. 
Horringer, Ely—the clay is thin, atid the sample came from near 
the base. The Woolpit samples were obtained from a well which 
was being sunk: the lowest, from some 60 feet down, shows very 
few granules. It is easy to suppose that thin beds, or lower parts 
of the clay, may have suffered some alteration. 
For the origin of these granules we naturally look to the Secondary 
clays and limestones. The dark clay frequently contains recognizable- 
fossiliferous boulders of Kimeridge materials, some exceeding 
12 inches across. Portions of these, on being pounded and washed, 
produce fragments closely resembling the granules of limestone. 
Granules in a specimen from a well at Colchester Green, Cockfield, 
contain visible microscopic fragments of black fibrous material 
similar to some fossils of the Gault. Grypheeas of the Lias are well- 
known inmates of the East Anglian Glacial Clays. All these: 
Secondary rocks rise to the surface west of the Suffolk area. The 
bulk of the materials which make up the matrix may well, therefore, 
have been brought from the west. 
I notice among most of the residues a few peculiar grains which 
differ markedly from the rest. They are always well-rounded, 
usually highly polished, in colour dark, most often brown; varying: 
in size, but seldom exceeding 0°5 millimetre. They are not seen 
in every sample; I have noticed none in the residues from Corton, 
League Hole, and Boston. These localities lie on or outside the 
eastern and northern boundaries of the dark-clay area. As I have 
also not noticed these grains in residues from Cromer, still farther 
north-east, there may be some significance in their distribution. 
Dr. G. J. Hinde, F.R.S., has kindly looked at some for me and says: 
‘They do not show any structure, aud I conclude that they are of inorganic 
Tue We 
aie = Petite win iit. 
