MINES OF RAVEN AND GUYOT HILLS. 
333 
zone of dikes rather than a single continuous dike. The junction of the dike with 
the Walter lode occurs at distances varying from 350 to 850 feet north of the Elkton 
shaft. In general the junction is farther north on the lower than on the upper levels. 
The general relation of the Walter and Raven lodes may be seen in fig. 34. 
South of the Elkton shaft the Walter lode and the accompanying Raven or 
Elkton dike become irregular and are less readily followed. The narrow fissure 
zone known to the north as the Walter vein here widens to a zone of intersecting 
and individually nonpersistent fissures at least 150 feet in width, as may be well 
seen on level 7 (fig. 34). Attempts have been made to identify one or more of 
these fissures with the Walter vein, but with little success. It seems more reason¬ 
able to conclude that, owing to certain geological relations presently to be described, 
the same forces which farther north produced the well-defined and regular Walter 
sheeted zone here produced a much wider zone of less regular Assuring, no single 
fissure of which can be selected as being alone the equivalent of the Walter lode. 
A third interesting fissure is the so-called Dead vein, an unproductive fault 
lying just north of the Thompson shaft. The Dead vein, or Thompson fault, as 
it may more appropriately be called, strikes N. 72° W. and dips 83° S. On level 
4 it passes about 100 feet north-northeast of the Thompson shaft, and has been 
followed for 80 feet in a drift. It is well exposed also on levels 5, 6, and 7 and 
shown to be a regular and persistent fault which is later than the Walter lode, slightly 
offsetting the basalt dike and the north-south fissure zone on all levels. It will be 
further described in the following section: 
GEOLOGICAL FEATURES. 
The prevailing country rock of the Elkton mine is breccia of the same general 
character as that exposed over the western half of Raven Hill. The Thompson 
shaft, however, and the workings immediately adjacent to it are in granite of the 
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