COAL-FIELD OF CLACKMANNANSHIRE. 125 



direction, and the brows of the alluvial hills have 

 their steep acclivity always to the west, and a long 

 easy slope in an easterly direction. The alluvial 

 cover is of very various depth, viz. from a few inches 

 to many fathoms. At one place to the westward 

 of Alloa, I found the recent alluvial cover upon the 

 side of the River Forth, to be 90 feet deep ; and 

 in one place, a little to the north of Alloa, the old 

 alluvial cover is no less than 162 feet deep. In the 

 recent alluvial cover of the River Forth, are found 

 trunks and branches of large trees, beds of sand, with 

 sea-shells, particularly of the oyster, cockle, mussel, 

 donax, &c. These beds of shells not only abound at 

 and below Alloa, but are found several miles to the 

 westward of Stirling in the same situation. The oys- 

 ter-shells are very large, and many of them of uncom- 

 mon thickness ; no recent specimens are now found so 

 large, nor are any recent oysters ever found above the 

 Queensferry. Horns of the stag, and bones of 

 large animals, have also been found, several of which 

 were produced when the former essays were read. 

 About three years ago, several very large bones were 

 found upon the rock-head, under a cover of clay, 

 in a bed of sand and oyster-shells at the foot of 

 Clackmannan Hill, which I particularly examined. 

 Some of these are now produced. Adjoining these 

 were two teeth, about five inches in length, shaped 

 like a cock's spur, about three-fourths of an inch 

 diameter at the base, and rounded at the point. 



