GEOLOGY OF NEW HAMPSHIRE 45 
The character of this final report may be summarized as 
follows: 44 per cent. of the pages is occupied with a description 
of the method of procedure and notes upon the geological and 
mineralogical results in the form of an itinerary; 20 per cent. 
relates to economic geology; 22 per cent. to agricultural geol- 
ogy and chemistry, and the remaining 16 per cent. is devoted to 
such miscellaneous topics as barometrical tables, the official 
documents relating to the survey, glossary and index. One of 
the assistants, was Professor J. D. Whitney, of Cambridge; Dr. 
E. E. Hale, of Boston, aided in the exploration of the White 
Mountains. 
The method of exploration or reconnaissance adopted by 
Dr. Jackson was based partly upon the structure. Knowing that 
the strata pursue a general northeast course, it was proposed to 
cross them several times at right angles to their outcrops, and 
also along the lines of strike. These lines divided the territory 
into triangular areas whose outside boundaries became known, 
and the various excursions for study were planned across several 
tracts, depending somewhat upon roads and settlements. Four 
cross sections are described and figured, viz., from Portsmouth 
through Concord to Claremont; from Concord to Wakefield ; 
from Concord to Winchester; from Winchester to Haverhill. 
There is also a longitudinal section along the Connecticut 
River from the Massachusetts line to Haverhill; and from 
Haverhill to the extreme northern part of the state. Six dis- 
tinctions are made: (1) Granite, syenite and gneiss; (2) mica 
slate; (3) hornblende rock; (4) argillaceous slate; (5) drift; (6) 
alluvium. Symbols indicate the location of twenty kinds of 
ores and minerals, quarries,. dips of strata and anticlines. 
The nature of the work was mineralogical. Scarcely any 
assistance was acquired from these reports for the later geolog- 
ical studies. The general view of age and structure presented 
was that of the older authors, all granite being regarded as 
“Primary,” and the dips of the strata outward in every direc- 
tion from an igneous center. This conclusion is best shown in 
an ideal section across northern New England. At the White 
