114 : THE JOURNAL OF GEOLOGY. 



found in the later series, with which they are doubtless in part 

 continuous. 



The granites and gneissoid granites are placed together, be- 

 cause between the two are constant gradations. If one speaks 

 accurately and includes among granites only those rocks which 

 are completely massive, the gneissoid granites include the 

 greater part of the granitic rocks ; for in large exposures it is 

 usually possible to find some evidence of foliation. The granit- 

 oid areas are of greatly varying sizes, running from small 

 patches to those many miles in diameter. When everywhere 

 surrounded by the schistose division of the Basement Complex, 

 they frequently have oval or ovoid forms. In nearing the outer 

 border of the granitoid areas, the foliation often becomes more 

 and more prominent, and near the edge of an area the rock fre- 

 quently passes into a well laminated gneiss. 



The schistose rocks include fine grained hornblende -gneisses, 

 mica -gneisses, chlorite -gneisses, and various green schists, for- 

 merly supposed to be sedimentary, but now known to be greatly 

 modified basic and acid igneous rocks. These schists have 

 usually a dark green or black color, are strongly foliated, and 

 the variations in strike and dip of this foliation, within small 

 areas, is very great. Not infrequently the schistose rocks are 

 traced by gradations into massive igneous rocks. 



The contacts between the schistose division and the granit- 

 oid division of the Basement Complex are usually those of in- 

 trusion, the granitoid rocks being the later. In passing from a 

 schistose to a granitoid area, small pegmatitic looking veins of 

 the granite are first found. In going onward these veins become 

 more numerous and, after a time, unmistakable dikes of granite 

 appear, which multiply in number and size in approaching the 

 granite area, until the granite is found in great bosses. Here we 

 have perhaps a nearly equal quantity of schistose and granitoid 

 rocks, and in this intermediate zone the schists may be found as 

 a mass of blocks within the granite, sometimes at but small dis- 

 tances from their original positions, the whole having frequently 

 a somewhat conglomeratic appearance. However, these pseudo- 



