J. E. 3farr— Studies in Lakeland. 299 



The f^neisses, of course, may have had an igneous origin, but they 

 certainly are not ordinary intrusive masses, and in any case I 

 believe that the crystalline limestone belongs substantially to the 

 same epoch. In other words there is nothing, so far as I can see, 

 to differentiate the rock in which Eozoon occurs (except this 

 peculiarity) from those other masses of crystalline limestone which 

 are found elsewhere intercalated in gneisses and coarsely crystalline 

 schists. How such rocks were produced is a question which is 

 highly controversial, and upon which, as I have already expressed 

 an opinion, I do not intend to enter. In this paper I have sought 

 nothing more than to state certain facts of which account must be 

 taken in framing any theory as to the origin of Eozoon. I M^ill 

 simply add that, to my mind, they offer a choice between two 

 interpretations only ; the structure is either a record of an organism, 

 or a very peculiar and exceptional condition of a pyroxene-marble of 

 Laurentian age, which is not a result of contact metamorphism in 

 the ordinary sense of the term. 



A 



HI. — Physiographical Studies in Lakeland. 



By J. E. Mark, M.A., F.E.S., Sec.G.S. 



3, The Eivers Caldew and Glenderamackin. 



TRAVELLER alighting at Troutbeck station (T of Figure), at 

 ^^ the summit level of the Keswick and Penrith Railway, finds 

 himself standing at the north-east corner of a moorland plateau 

 (Matterdale Common), having a mean height of over 1000 feet, 

 and sloping gradually down to the River Glenderamackin (G), 

 which bounds it on the north. The moorland is thickly covered 

 with drift, and rock exposures are scarce, except here and there in 

 the tributaries of the Glenderamackin, which run in a northerly 

 direction from the Helvellyn Range, the principal being Trout- 

 beck (T B) and Mosedale Beck (M B) ; (the latter is one of many 

 of the same name in the district). That the stones in the drift 

 were mainly brought from the Helvellyn Range is easily seen after 

 a very slight examination ; the boulders consist mainly of the more 

 altered ashes and lavas derived from the Borrowdale series of the 

 Helvellyn Range, with occasional boulders of the type of quartz- 

 felsite dyke which penetrate the rocks of Helvellyn and its minor 

 ridges (the best known being the familiar "Armboth and Helvellyn 

 Dyke"); whilst the "Eycott" type of volcanic rock, occurring 

 north of the main outcrop of Skiddaw Slates and having its nearest 

 exposure within a mile of Troutbeck station, is entirely unrepresented. 

 At the north-east corner of the moorland, close to Troutbeck station, 

 a few boulders of mountain limestone indicate the point where the 

 erratics from Helvellyn are beginning to be replaced by others 

 brought from the eastward. The drifts of this moorland and of 

 the region to the north have caused the interesting changes in the 

 drainage of the area which it is the main object of this paper to 

 describe. 



