TEH UANTEPEC ROUTE. The well-known geo graphic conditions at Tehuantepec and between the Nicaragua and Panama Canal routes made it unnecessary to explore those parts of the Ameri can isthmus for other possible locations for an interoceanic canal, and the commission mentioned limited its investigations to what is generally known as the Darien country, extending from Panama to the Atrato River.
For about 80 miles the width of the isthmus in this region does not exceed 40 miles, except at one or two headlands which project beyond the general line of the coast. The narrowest point is at San Bias, where the distance from Mandinga Harbor to the shore of Panama Bay is only 31 miles, two miles less than from the head of the bay at Limon, at Colon, to the mouth of the Ber nadine. On the eastern side of Panama Bay, about 100 miles from Panama, an estuary known as San Miguel Bay extends into the interior to within 33 miles of Caledonia Bay, on the Atlantic side. This bay of San Miguel, .on the Pacific, and San Bias and Caledonia bays, on the Atlantic side, afford excellent harbors and canal ap proaches. Between Panama and San Bias the ridge of the Cordilleras crosses from the Pacific to the Atlantic side and continues there to the mouth of the Atrato River.
As the existence of practicable and feasible routes in this section depended upon the height and continuity of the divide, its crest was ex amined all along the line, with as much care and accuracy as was practicable under the conditions which existed, for the discovery of gaps and de pressions, so as to ascertain whether any were sufficiently low for canal purposes, and measure ments were made of those which promised the most favorable results.
The ridge was traced continuously on the ground from the head of the river Carti, a little east of Mandinga Ilarbor, in San Bias Bay, to the head waters of the Chagres, and thence down the river to the Panama Railroad a total distance of 24V miles; also near Coledonia Bay from the Carreto summit, to the Sassardi summit, a dis tance of 27V, miles. The lowest elevation in the former section was 956 feet, in the latter 6S3 feet. Between these two sections from San Bias Bay to Caledonia Bay, a distance of Sl miles in an air line, and from Caledonia Bay southward to the Atrato River, the examination was made from the sea, and the elevations of the higher peaks, as well as the gaps and their distances were determined. The result showed that there was no probability of any suitable depression within these limits.
In addition to these investigations, a survey was made from San Miguel Bay, on the Pacific side, up the Chucunaque and Chucurti (Sucubti) rivers, which was almost though not quite con nected with the work done near Caledonia Bay. After the results of the general exploration were determined, the examination of other possible routes was limited to those sections where the isthmus was narrowest, where the coast lines of fered good harbors, and the indications along the divide were the most promising. These condi tions were found near San Blas Bay and Cale donia Bay. East of San Miguel Bay the isthmus widens, and no route can be expected there less than a hundred miles in length.