'{ganong] peat BOCiS OF NEW BRUNSWICK 145 



-strip, on another. The Spruce Luke bog, of about the same size, is more 

 irregular in outline than either of the others, and more mixed as to its 

 raised and flat parts, and it has on it three ponds (at least one on ihe 

 raised part), and shows rocky ledges breaking through it at one place, 

 •and here and there tree-bearing islands, which occur also on the Lepreau 

 bog. Near New Eiver there is a remarkable bog, higher above the sea 

 :and very much drier than the othei-s, and held up apparent]}' by rocky 

 iedges. 



A striking and important feature of these bogs is the raised form. In 

 •cross section the surface rises at tirst rather abruptly, then more gently, 

 and finall}' on top may become gradually flattened to a level, as is shown 

 by tigures 4 and 5, made from actual levels.' Theoretically the raised 

 parts form convex curves, most abrupt at the margin, and less curved on 

 the tops, as is shown by the exaggerated vertical scale of flgure 6. The 

 cause of this form will be discussed later. The angle of slope is shown in 

 true scale in figures -t and 5, but they are not extreme cases. At the 

 Spruce Lake bog 1 estimated a Slope near the highway road as rising 

 6 feet in 66. a slope of 1 in 11. At the Lepreau bog I found by a level, 

 near the river, east of the point D, Fig. 2, a slope of 8 feet in 39-8 inches, 

 or 1 in 5 ; at another place, by what seemed a water outlet, then dry, it 

 was 8 feet in 21. or more than 1 in 3, and in one part of this it Avas 5 feet 

 in 5*10 inches. The latter slopes are, however, probably determined by 

 local conditions, apart from the bog structure. Not all slopes on the bog 

 are steep, for some of them merge down very gi-adually into the flat bog. 

 It is ditficult to estimate the height above the margin, since it is im- 

 possible to say exactly what the margin is. The results of my levels 

 were as follows : 



Lepreau hoij. Height of highest point X above claj^ at A (fig. 2), 

 three levels at different times, 13 ft. 3^ in. (Sept.), 

 13 ft. 4i in. (July), 12 ft. 11 in. (July). Mean, 



Va ft. -iCin:' 



Height of X above water in Little Lepreau river at D (fig. 2), two 

 levels, 23 ft. 3 in. (July), 22 ft. 8 in. (Sept). Mean, 22 ft. 11^ in. 



1 These levels were taken by myself and an assistant, with a simple home-made 

 level consistinpj of a good brass spirit-level, to which was attached a straight glass 

 tube of small bore for sighting through, tlie whole attached to a brass joint, which 

 could be adjusted at any angle, mounted on a tripod. That this instrument gave 

 fairly accurate results is .shown by the fact that three distinct lines of level at dif- 

 ferent times, and by different routes between the same points, varied by only a few 

 inches. I consider the error in these heights is not greater than six inches. 



- The differences may be due to error of the instrument, but allowance must also 

 be made for both daily and seasonable variations in height of the bog, discussed 

 Jater. 



