Cope.] 148 [Oct. 16, 



reached. The foot of the precipice is perhaps 400 feet below the coal bed, 

 and at its foot is a gently sloping plateau of perhaps a quarter of a mile in 

 width. The slope than becomes more abrupt, and descends to the bottom 

 of the ravine-like valley, 500 feet below. At a depth of fifty feet verti- 

 cally below the foot of the precipice at the beginning of the steeper slope, 

 the upper bed of this part of the Galiana crops out. It is one foot in thick- 

 ness, and is of good quality. Some eighteen inches of clay intervene 

 between it and a second bed of coal of about three feet in thickness. 

 About forty feet below their level is a bed of impure lignite eighteen 

 inches thick ; and below three or four feet of clay is a bed of better lignite 

 which varies from two to six inches in thickness. Below this are about 

 eighteen feet of carbonaceous clay and shale, and below this fifteen feet 

 of clay with thin seams of lignite. Below this succeed white slates and 

 clay with vertebrate fossils, chiefly three-toed horses, but no more coal. 



The workable beds of coal in this property are the. eighteen inch bed 

 above the precipice, and the eighteen and thirty-six inch beds below the 

 precipice. At present these beds are only exposed in open cuts. Those 

 below the precipice have a quarter mile (English) extent to the trap 

 dyke, while their extent parallel to the dyke is probably considerable. In 

 fact, the coal formation follows the borders of the dykes at varying dis- 

 tance, and the outcrop thus has many miles of extent. The workings on 

 the Galiana property consist of nothing but the open cuts mentioned. 

 The clay is of excellent quality, and is manufactured by the owner into 

 roofing tile. 



The Hulla and Juarez mines are on the other sides of the same trap 

 plateau. The highest coal outcrop of the Hulla is above the dyke preci- 

 pice on the opposite side from the highest exposure on the Galiana, and is 

 probably the same bed. This will therefore be about a third of a mile 

 between the two outcrops. The bed is, however, thinner on the Hulla 

 side, being only six inches in depth. The same is tme of the other out- 

 crops on the Hulla side. The second one is perhaps 500 feet lower down 

 towards the bottom of the valley. There are open cuts, but the principal 

 exposure is clay, carbonaceous and otherwise, with a bed of pure lignite of 

 six inches thickness. At the Juarez outcrop, several hundred feet lower 

 down, the lignite bed is only an inch in thickness. 



The Concha and Providencia mines lie south-east of Zacualtipan, and 

 below the trap precipice already described. They are, however, near to 

 another mass of trap which may be a part of a different, or a branch of the 

 same great dyke. The Concha is developed by both an an open cut and a 

 timbered drift. The bed of coal varies from thirty to eighteen inches in 

 thickness, and lies between more or less shaly beds of clay. They all dip 

 at a low angle towards the trap. This coal looks well, but the extent of 

 the bed in one direction is probably reduced by the not far-distant dyke. 

 Lower down the hill we sought for another outcrop on the Concha prop- 

 erty, but it had been covered up. An eighth of a mile round the hill from 

 this lower level, in the side of a ravine is a cut, which displays the bed of 



