560 CENTRAL MINERAL REGION OF TEXAS. 



2. LONG MOUNTAIN SERIES. 



Such rocks as belong to the Burnetian trend, which carry garnet, serpen- 

 tine, and the heavier green and dark colored iron bearing minerals, are for 

 the present classed in a separate series. They occupy belts parallel with the 

 axes of the Lone Grove Series and lying between them. Exposures occur 

 on Clear Creek and Spring Creek, in Burnet County, and in the country adja- 

 cent to Long Mountain, in Llano County, as well as in the heart of the King 

 Mountains farther west. The soapstone of Llano County is largely, if not 

 wholly, in this terrane, and serpentinous rocks mark its course in Gillespie 

 County. Mason County has also some good exposures. 



3. BODEVILLE SERIES. 



A marked aggregation of micaceous schists extends in belts alternating 

 with the Lone Grove and Long Mountain series in the same Burnetian trend. 

 It is not known that any of these rocks carry accessory minerals of particular 

 value, but some of them possess qualities which make them useful as they are 

 for special purposes. 



2. FERNANDIAN (ONTARIAN) SYSTEM. 



One of the most important systems, considered economically, is the Fernan- 

 dian, which has a trend almost exactly northwest by the compass. Its true 

 course is north 36° west, but in practice it will be more convenient to follow 

 the ordinary compass bearing. Care must be taken, however, to make numer- 

 ous observations in order to avoid errors which may arise from local attrac- 

 tion by the large deposits of iron ore which occur in these strata. The rocks 

 here included commonly dip at angles above 35°, and from that pitch to 

 vertical or nearly so. They may be found involved in later uplifts, as in a 

 narrow belt west of Packsaddle Mountain, in Llano County, but it is not usu- 

 ally difficult to recognize them in good exposures, comparatively few of which 

 fail to show some evidences of the original course. The vast beds of the 

 richer iron ores and other accumulations of economic importance will cause 

 this system to become better known than any other in the region, so that the 

 only precaution necessary in most cases is to avoid confounding the Fernan- 

 dian rocks with some similar deposits of the later Texian System, the different 

 trend of which is rarely inappreciable. The Fernandian strata have been 

 much folded and subsequently denuded, resulting in numerous bands or belts 

 traversing the country in which they are predominant. Besides the iron ores, 

 important manganese ores, graphite, marble, etc., are very abundant, and the 

 outcrops of these often aid materially in tracing the former. In all the com- 

 plete sections yet examined there are practically seven distinct beds, which 

 admit of a fairly satisfactory grouping into three geologic series, as below: 



