Page:Vol 6 History of Mexico by H H Bancroft.djvu/704

684 In latitude 19° 18' 30", longitude 94° 33' west of Greenwich, we found large deposits of iron-sand, and what, perhaps, may be gold. It is not mica, and although the little bright particles might be copper or iron pyrites, still they could be sensibly flattened by pressure.

Above this point rapids are met at every bend, and the river is constantly breaking through new channels, though these changes are circumscribed to very narrow lateral limits. Four rompidos are found here in less than two miles.

During our journey, all the officers made independent notes and observations, which, being compared at night, were found to agree very fairly while on the Coatzacoalos; but after entering the Jumuapa, it was found impossible to compare our notes satisfactorily. This river and the Sarabia are said by Señor Moro to descend from the Guienagate Mountains. Finally, we passed the Fortuguero Brook, which enters the Jumuapa on its left bank, and all the surveying parties landed at La Puerta on December 6th, after eight days' canoe travelling.

. — After leaving La Puerta, we reached the picturesque plains of Sarabia; travelling on mules over very bad roads.

The whole district up to San Juan Guichicovi is made up of red clay in its plastic state, and slates of several colors, and of all degrees of hardness and denudations. Compact limestone here makes its first appearance in our journey, and its constant association with silicates indicates the presence of hydraulic limestone.

The extensive district of San Juan Guichicovi contains jasper and argillaceous limestones. From the latter a good cement is made, as can be attested by the huge pile of this material opposite the old unfinished church commenced by Cortes.

While passing through this wild and romantic region, we crossed the Mogañe and Pachiñe, both torrent streams, tributaries of the Malatengo, and of no value to our purposes, being low as to elevation and insignificant as to volume.

The geological features of the country do not again change much until after crossing the Malatengo near its junction with the Citune River. The clay then becomes more sandy, compact limestone forms the base of the mountains, and gray slate and quartz bowlders are seen in abundance.

In the neighborhood of Petapa, a greenish slate was often met with, and on the road I picked up a piece of blue and green malachite.

Gaining very little information here, we left for El Barrio, after taking note of the traditional rumor about some large lakes in the Petapa Mountains.

Leaving El Barrio, we crossed several small dry streams, and lastly, came to the Almoloya, which was spoken of as the great dependence of the summit-level. We found it about 20 feet wide, with a sluggish current, and hardly 6 inches deep. Its bed of sand and gravel was often dry, the water percolating through the gravel. What we had seen convinced me of the impossibility of using the streams that could be found high enough for supplying the summit-level of a ship-canal.

Still, to place these facts beyond doubt, transit and level lines were run,