C. H. Hitchcock — Crystalline Rocks of Alabama. 279 



Lower Silurian limestone — is abundant. Near its eastern bor- 

 der are quarries of white marble not distinguishable in its 

 appearance and general geological position from that of western 

 Vermont. Not far removed from it is the familiar quartzite 

 with its Scolithus — the same rock whether in Vermont, Penn- 

 sylvania, Virginia or Alabama, and it everywhere forms moun- 

 tain ranges, as about Talladega and Anniston. As in Vermont, 

 so in Alabama it requires close study to discover the true 

 relations between this sandstone, the marble and the various 

 limestones. The calcareous portion attains a greater thickness 

 than in the north and it has been well divided by Professor 

 SafFord in the various members of the Knox group, which have 

 not yet been identified seriatim (to my knowledge) north of 

 Virginia. 



The range of mountains immediately adjoining these lime- 

 stones has the Ocoee group of Safford upon its western flank 

 and summit, and it attains the highest elevation of any of the 

 summits, and is to be compared with the foot hills of the Blue 

 Eidge which sometimes surpass the main ridge in magnitude. 

 The rocks are greenish and drab slates and schists, argillaceous, 

 nacreous and hydromicaceous, together with layers of quartz- 

 ite which in some localities attain great thicknesses. Grains 

 of quartz presumably water-worn, are disseminated through 

 many of the schists. All the strata dip southeasterly, more at 

 first than afterwards, so as to give the aspect of an overturned 

 anticlinal. Small veins of quartz, cavernous through decom- 

 position and with bunches of chlorite, further characterize this 

 group. I find from Safford's descriptions that the rocks of 

 the typical area of this formation in Tennessee are similar. I 

 have not seen much of this member in Virginia. Whatever 

 of it is to be found there was placed by W. B. Eogers in his 

 formation No. 1. But the exact analogue of this group is to 

 be found in the magnesian slate of Emmons in western New 

 England and eastern New York, whether it be Lower Silurian, 

 Acadian or Huronian ; a hundred typical specimens collected 

 in Alabama could not be distinguished from a corresponding 

 number obtained in the Taconic Mountains of western New 

 England. This character is uniform in the three places where 

 I observed it, near Anniston, Talladega and Syllacauga. 



The next band of rock, usually just to the southeast of the 

 crest of the mountains, is a feldspathic mica schist, or an im- 

 perfect gneiss. It resembles the inferior grades of the Green 

 Mountain gneiss of Vermont. Near Ashland a few ledges 

 remind one of the schists of Mt. Washington, N. EL, but no 

 more so than does the Green Mountain rock. There is not 

 enough of this rock to enable us to call it Montalban. 



Two bands of a newer schist are intercalated within this 



