NATURAL HISTORY. 
elay small veins of coal resembling reeds and grass 
are found, and retinasphaltum ; the whole is cover- 
ed by a loose gravelly head. 
The main beds of this formation appear very ob- 
viously to consist of the wood ef Dicotyledonous 
trees imperfectly mineralized, 
ALLUVIAL DEPOSITS. 
The principal are those of the Teign and Exe ; 
they accumulate with considerable rapidity, especi- 
ally along the sides of the latter river, but offer 
nothing very peculiar to remark on—in cutting 
through the soil in order to lengthen the Exeter 
canal, successive layers to the depth of several feet, 
of bivalve shells, chiefly of the genera Tellina and 
Mactra might be observed, marking the different 
depositions of sediment. 
We have thus given an outline of the different 
strata of the neighbourhood, but to enter into any 
lengthened Disquisition as to their relative ages and 
modes of formation, would require a larger space 
than is compatible with our limits, Arguments 
deduced both from Chemistry and the higher Ma- 
thematics mduce a general belief of the once fluid 
state of the primitive rocks, and the more modern 
