March, 1931] LAND SURVEY OF DURHAM 7 



The swamp and open water type took all lands too wet to grow any- 

 thing })ut buueh grass and alder. This was not subdivided. 



All lands more than half covered with hardwood growth other than 

 gray birch were classed as hardwoods, subdivisions being made on the 

 basis of age of the stand and the density of white pine. 



The gray birch type followed the same rule, claiming all lands more 

 than half gray birch, and subdivided by age and the density of pine. 



Similarly, the pine type took all lands predominantly pine with age 

 and density subclasses. 



In dividing these classes by age. ten-year classes were used. That is, 

 areas with trees between and 15 years old were classed as 10 years. 

 Accurate measurement of ages was confined to counting the whorls 

 of pines. 



The density classes were not as standard. Lots were grouped 

 in five classes; those having pine: "scattered," 1/10, 3/10, 6/10 or 

 .8/10 covered. An area called hardwoods 10-3/10 for example, would 

 be covered, for the most part, with 10-year-old hardwoods, but 

 3/10 with 10-year-old pine. Pasture unevenly scattered would be prac- 

 tically open pasture, with a few old and a few young pines here and 

 there. 



In making the notes in tallies and on the map it was necessary to use 

 abbreviations, and the following were adopted : 



Hay : Hayland 



Past : Pastureland 



Hd or Hdwd : Hardwoods 



WP or Pine : White Pine 



GB : Gray Birch 



10, 20 etc.: Age (10, 20 yrs. etc.) 



Sc: Scattered (density) 



1. 3. 6 or 8: Density (1/10, 3/10, 6/10 or 8/10) 

 Swamp land was shown by the standard symbol of a clump of grass. 

 An area marked GB 20-1 means a 20-year-old stand of gray birch, 

 1 10 pine. \YP 40-8 means a 40-year-old pine lot. 8/10 density. In 

 a few cases it was necessary to go farther, as in a stand labelled Hd. 

 40-WP 10-1, which would represent a hardwood stand 40 years old, 

 with 1/10 of the ground shaded by 10-year-old pine. In a table this 

 would be simplified and placed in the Hd 40-1 class. 



RESULTS OF THE SURVEY 



Durham is in Strafford County, in the southeastern part of New 

 Hampshire. It is about five miles south of the city of Dover, and 

 borders on the towns of Lee, Madbury and Newauarket with Great 

 Bay to the east. The Dover branch of the Boston and Maine Railroad 

 passes through, running northeast and southwest. 



The bed rock of the town is of three types. A wide belt of eruptive 

 rock formation takes in most of the town and is a part of an inter- 

 rupted belt which follows the coast through neighboring towns. The 

 coastal formation is quartzite. while a strip down the Lee line is com- 

 posed of slaty schists. The soil has been altered by glacial action both 



