92 THE CRYSTALLINE ROCKS OF CECIL COUNTY 



To the east of Bay View, Little Elk and Big Elk creeks again 

 uncover the granite-gneiss. Between Childs and Leeds on Little Elk 

 Creek, there are excellent exposures of granite-gneiss. It is here a 

 somewhat darkly colored, massive hornblende-granite, carrying very 

 little biotite. The strike of the schistosity is N 60° E and the dip 

 30° to the southeast. 



The same rock shows itself all the way up the creek to the crossing 

 of the road from Blue Ball to Eair Hill. On Big Elk Creek the first 

 exposure is some five-eighths of a mile south of Banks, where there 

 is a small abandoned quarry by the roadside showing a massive 

 biotite-granite-gneiss. Erom this point up the stream to Appleton 

 the rock is exposed at intervals. It bears both micas and sometimes 

 hornblende also. 



As the granite-gneiss approaches the mica-gneiss it becomes more 

 micaceous and the separation between them is sometimes an arbitrary 

 line. Large exposures, however, show a distinctly sedimentary char- 

 acter in the latter and an igneous character in the former. Except 

 where it approaches the mica-gneiss the granite-gneiss shows an 

 increasing basicity both to the north and to the south. 



The granite-gneiss is thickly traversed by quartz veins and basic 

 dikes. Scarcely a quarry is free from these dikes. Within a distance 

 of less than a quarter of a mile thirteen such dikes occur. There are 

 also larger intrusive masses exposed at Blythedale, Theodore and Bay 

 Yiew. These and the more important dikes will receive separate 

 treatment. 



Throughout the level portions of the plateau, quartz vein-rock 

 is universally distributed and is made use of as road-material. There 

 are also numerous limited bands of red soil mixed with fragments 

 of decayed amphibole-schist. 



This soil, with the associated amphibolite, undoubtedly represents 

 basic dikes. As they can not be traced continuously and were usually 

 quite limited in width, they were not, in most cases, mapped. 



Gabbro and aLet a- Gabbro.— The belt which borders the granite- 

 gneiss on the north is composed of gabbroitic rocks — hypersthene- 

 gabbro or norite, quartz-hornblende-gabbro, hornblende-gabbro or 



