ACCOUNT of PEAT-MOSSES, &c. 267 



cd in the extent above mentioned, except that the Dript rock is 

 continued acrofs the river, and that another rock alfo croiles it, 

 at what are called the cruives of Craigforth, and gives a consi- 

 derable obftruction to the Stream, fo as to prevent the tide from 

 flowing up farther. Throughout the reft of the carfe, no 

 ftones whatever are found in the foil ; but beds of fea-fhells, 

 particularly oyfter-ihells, appear in many places of it, as in 

 ditches, where the earth has been dug to a certain depth, 

 and in the banks of the Forth and its branches. A bed 

 of this kind, of considerable thicknefs, is to be feen near 

 the bridge of Goody, a fmall river that runs into the Forth ; 

 and another is to be feen in a bank, on the fouth fide of the 

 road between Polmouth and Borrowftounnefs. When the Forth 

 encroaches upon its banks, it alfo difcovers large logs of tim- 

 ber at various depths in the clay. 



Concerning the river it may be necefTary to remark, that 

 the tide flows as far as the bed of rock near Craigforth, al- 

 ready mentioned, which is about 300 yards below the junc- 

 tion of the Teith and Forth. Above this point, the furface of 

 the river is four feet and a half higher than the furface below, 

 even at fpring tides. The only other fall in the river from that 

 place to Cardrofs, where the carfe terminates, is one of three 

 feet at the ford of Frew, about eight miles diftant from the 

 former, in a Straight line. 



It will ferve to give fome idea of the flatnefs of this country 

 to obferve, that by a furvey taken of the river, with a view to ren- 

 der it navigable, it was found, that a dam four feet in height, 

 erected at the point of Craigforth, would increafe the depth of the 

 river more than three feet as far up as the ford of Frew ; and 

 that one of five feet in height, erected at Frew, would make a 

 like addition to the depth of the river, as far as the ford of Car- 

 drofs. The height therefore of the furface of the Forth, at the 

 ford of Cardrofs, above the high water mark at the cruives of 



LI 2 Craigforth^ 



