NJDEP - NJGS - First Annual Report of the Geological Survey of the ...

prinelpal points were established by a reoonnoissance, in orderthat the topography might be checked by a secondary triangulationwhen a theodolite could be procured. A second baseline was afterwards measured in the township of Wantage, andthe same eours6 pursued as in Montagne, and so on for all thetownships that were surveyed. But one plane-table was in useuntil September, when one was borrowed from the Coast Sur"vey, and afterwards a theodolite from the same source. Fromthe beginning of the _ork, Professor Baehe, the Superintendentof that Survey, has tal_cn a cordial interest in its progress, andexpressed a willingness to aid it by any means in his power.A summary of the operations of the past season is as follows:--Theparty entered the field on the eleventh of July,consisting of three principal assistants, aided" by four volunteers,who gave their services in return for learning engineering.Three more assistants were added when the instrumentswere received from the Coast Survey. On the 30th of No.vember the field operations were brought to a close. During. that period, the parties completed three hundred and sixty-onemiles of tbpography, (being three fourths of the county ofSussex,) and seven hundred miles of levelling for geologicalsections, besides many minor details. In consequence of thelate period at which the theodolite Was received, and theinadequacy of the means, the complete triangallation of thecounty was not accomplished, but enough was done to test thegeneral accuracy of the topography. A sketch of this accompaniesthe report. Since the parties left the field, a sufficientlength of time has not elapsed to complete in the office all ofthe work which has been done, but so much as may be mappedat the time the subject occupies the attention of the Legislature,will be forwarded to Trenton for inspection. The scaleupon which it is' proposed to execute the map, is 1-80,000,the same as the published maps of the Coast Survey, and asthe topographical map of France. This is somewhat less thanone inch to the mile, which is the scale of the ordnance map ofEngland. The scale proposed for the county maps is 1-80,000,or about two inches to the mile.99NEW JERSEY GEOLOGICAL SURVEY