U. 8. Coast Survey Reports—1861 and 1862. 97 
Of manuscript maps and charts, two thousand one hundred 
and eighty-one had been constructed; and of engraved maps 
charts and sketches, there had been produced four hundred and 
ninety-three, 
The triangulation extends from Passamaquoddy Bay on the’ 
northeast boundary of the United States, to Matanzas inlet on 
the east coast of Florida below St. Augustine, with a single 
interruption of about sixty miles on the coast of South Carolina. 
From Cape Florida it extends over all the line of the Keys to 
the Tortugas, It embraces also some portion of the western 
coast of the peninsula. From St. Marks it is continuous through 
St. George’s Sound; it embraces Pensacola harbor, the Perdido 
entrance, Mobile Bay, Mississippi Sound, Lake Borgne and Lake 
Ponchartrain as far as New Orleans. A branch triangulation 
extends also through Isle au Breton Sound to the mouth of the 
Mississippi river. West of the delta it covers most of the coast 
of Louisiana and Texas. 
On the Pacific coast, the survey has been less connected ; 
but it embraces all the principal harbors, headlands and an- 
chorages. 
The triangulation is on many portions of the coast considera- 
bly in advance of the topography and hydrography. This is 
particularly the case in Maine, in the Gulf of Mexico and on the 
northwest coast. Upon the Maine and Pacific coasts the work 
Is being actively advanced. Energetic reconnoissances have 
also been made in the Gulf, between Mobile and New Orleans, 
since the outbreaking of the war. : 
One of the most important of the surveys made during the 
year 1862, was that of the Potomac river from near its mou 
up to Georgetown. Connected with this may also be mentioned 
important topographical surveys of the country around Wash- 
ington. 
‘he survey of the Florida reefs was also energetically pursued 
during the same period. ; 
The hydrographic operations of this year of which the results 
have probably been most immediately valuable, are those upon 
he coast of North and South Carolina and of Georgia. Hatteras 
Inlet, Oregon Inlet, the Neuse river to a point above Newbern, 
the Harbor of Beaufort with its entrance, were surveyed or 
Tesurveyed so soon as the progress of naval and military opera- 
tions had opened the*way, to the great subsequent advantage of 
our commanders. ; : 
In like manner, on the coast of South Carolina, Georgia and 
‘lorida, similar operations were carried on after the occupation 
of Port Royal. Stono inlet and river, Folly and Kiawah rivers, 
and N. disto river, were resurveyed and sounded out, the 
channels being found in some of them to be entirely chan 
Am. Jour. Sct.—Szconp Serres, VoL. XXXVII, No. 109.—Jan., 1864. 
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