C 567 3 
XXIII. Account of a Substance found in a Clay -pit ; and of 
the Effect of the Mere of Diss, upon various Substances im- 
mersed in it. By Mr. Benjamin Wiseman, of Diss , in Nor- 
folk. Communicated by John Frere, Esq, F. R. S. With an 
Analysis of the Water of the said Mere. By Charles 
Hatchett, Esq. F. R. S. In a Letter to the Right Hon . Sir > 
Joseph Banks, Bart. K. B. P . R. S. 
Read April 19, 1798. 
rp 
1 he substance I have inclosed was found near Diss, in a body 
of clay, from five to eight feet below the surface of the soil. 
All the pieces I observed laid nearly in a horizontal direction; 
and varied in size, from two or three ounces, to as many pounds. 
The colour of the substance, when taken fresh from the clay'-pit, 
was like that of chocolate ; it cuts easily, and has the striated 
appearance of rotten wood. The pieces were of no particular 
form ; in general, they were broad and flat, but I do not re- 
collect to have met with a 1 piece that was more than two 
inches in thickness : it breaks into laminae, between which are 
the remains of various kinds of shells. The specific gravity of 
this substance, dried in the shade, is 1 .588 ; it burns freely, 
giving out a great quantity of smoke, with a strong sul- 
phureous smell. 
By a chemical analysis, which I cannot consider as very 
accurate, one hundred grains appear to contain. 
