found near Brentford, 133 



Thames at low water. The strata here are first, sandy loam 

 from six to seven feet, the lowest two feet slightly calcareous. 

 Second, sandy gravel a few inches only in thickness. Third, 

 loam slightly calcareous from one to five feet ; between this 

 and the next stratum, peat frequently intervenes in small 

 patches of only a few yards wide, and a few inches thick. 

 Fourth, gravel containing water ; this stratum varies from two 

 to ten feet in thickness, and is always the deepest in the places 

 covered by peat ; in these places the lower part of the stratum 

 becomes an heterogeneous mass of clay, sand, and gravel, 

 and frequently exhales a disagreeable muddy smell. Fifth, 

 the main stratum of blue clay, which lies under this, extends 

 under London and its vicinity, the average depth of this clay 

 has been ascertained, by wells that have been dug through it, 

 to be about two hundred feet under the surface of the more 

 level lands, and proportionably deeper under the hills, as ap- 

 pears from Lord Spencer's well at Wimbledon, which is five 

 hundred and sixty-seven feet deep. This stratum, besides 

 figured fossils, contains pyrites and many detached nodules; 

 at the depth of twenty feet there is a regular stratum of these 

 nodules, some of which are of very considerable size. 



In the first stratum, as far as my observation has extended, 

 no remains of an organised body has ever been found, and as 

 my search has not been very limited, I may venture to say 

 it contains none. In the second stratum, snail shells, and the 

 shells of river fish have been found, and a few bones of land 

 animals, but of inconsiderable size, and in such a mutilated 

 state, that it cannot be ascertained to what class they belong. 

 In the third stratum, the horns and bones of the ox, and the 

 horns, bones, and teeth of the deer have been found, and also, as 



Ta 



