EDEN VALLEY AND YORKSHIRE-DALE DISTRICT. 57 



kinds of rock are easily distinguishable in any section of drift where 

 they may happen to be intermingled. 



The Silurian inliers extend only about two or, at the most, three 

 miles into the Dale district. Northward from that the Dale rocks are 

 wholly Carboniferous, and generally speaking may be said to consist 

 of: — a lower series of limestones, sandstones, and shales, the last pre- 

 dominating over a large part of the area that this paper refers to ; 

 and an upper series, which commonly occupies the higher ground, 

 and consists of alternations of grits, sandstones, and shales. Occa- 

 sional thin limestones are found in part of the area, but they are 

 usually distinguishable in lithological character from the thicker 

 limestones of the lower group. Except that in one part of the Dale 

 district there are a few veins of silicified limestone of acharacter suffi- 

 ciently well marked to allow them to be used as tests of the way 

 that the drift moved, but few rocks are found of such a character 

 that one may identify fragments of them amongst the drift derived 

 from other rocks in the neighbourhood. Fortunately, however, the 

 highest thick limestone of the Yoredale rocks is so much unlike any 

 of the beds above it that it may be safely used to determine this point. 



Along the western border of the Dale district the case is far 

 otherwise. The long line of faults joining the Craven- and Cross-Fell 

 branches of the Pennine faults may be said, for more than half its 

 length, to mark off the Silurian area from that occupied by the 

 Carboniferous rocks. 



Northward from Leek to near Sedbergh the Carboniferous rocks 

 abut directly against the Silurians ; but beyond this, strips and 

 patches of the red conglomerates of the Upper Old Ked, and occa- 

 sional strips of the peculiar apple-green quartz conglomerates of the 

 Lower Limestone Shale, appear at intervals among the faults to a 

 point about two miles south of Rawtha bridge. Both of these rocks 

 are quite unlike either the Silurian or the Carboniferous rocks that 

 they are faulted amongst ; they may therefore in most cases be 

 relied upon as tests. 



Just to the north of the inliers of Upper Old Eed and Lower 

 Limestone Shale alluded to, bosses of diorite come in the Lower 

 Silurian rocks near the faults. Portions of it are of a well-marked 

 character, and can easily be identified amongst drift stones from any 

 of the rocks around. 



Passing onwards to the Eden valley, we come upon the peculiar 

 deposit that is locally known as " Brockram." This is a breccia, or a 

 series of breccias, of fragments of Carboniferous rocks, mostly of 

 limestone, in a red sandy matrix, forming a rock of great durability, 

 that comes to the surface as a strip varying in width from 1 to 3 

 miles. In no instance known does the Brockram in the Eden valley 

 lie higher than 700 feet above the sea; most of it lies between 

 the 500- and 600-foot contours. Its principal areas of outcrop lie to 

 the south of Kirkby Stephen, and near Appleby, to the north of 

 which the rock is generally less compact and durable, and in large 

 masses is distinguishable from that which occurs in the typical areas. 

 A few exposures of Brockram occur at intervals in the low ground 



