Notes and Comments. es - 
lations of animal debris in the deeper parts of the clear water. 
These thickened masses everywhere wherever they were found 
presented a very remarkable paleontological ‘ facies.’ The 
assemblage of fossils represented in them was found nowhere 
else, and it was impossible therefore to conceive that they could 
have been squeezed up from the horizontal beds which were 
found wrapped round about them. They could only have 
been original depositions. Dr. Vaughan spoke with warmth, 
and the chairman, Professor Grenville Cole, who, apparently, 
did not enjoy ‘a scrap’ so much as most Irishmen, had to 
interpose to bring the discussion back to calmer waters. 
THE MIDDLE TEES AND ITS TRIBUTARIES: 
Mr. C. B. Fawcett, wrote :—The streams here considered 
are the middle portion of the Tees and its tributaries from 
Stainmore to the eastern edge of the Carboniferous rocks of the 
Pennines. The district which they drain is characterised by 
the presence of three distinct types of topography, viz.: (1) 
A wide and comparatively smooth upland surface, sloping 
gently eastward, but cut off abruptly to the west by the Pennine 
Scar, with a few hills rising above it; (2) A series of wide, 
shallow, mature valleys; (3) A series of narrow and youthful 
valleys, which are for the most part sunk below the floors of 
the mature valleys. The rocks of the district are almost 
entirely of Carboniferous age, mainly Lower Carboniferous 
limestones and shales in the southern half and Upper Carbon- 
iferous sandstones and shales in the northern. The complex 
topography is not primarily due to the rock structure, which 
is quite simple ; but must be ascribed mainly to the work of 
the streams, influenced in some cases by lines of faulting. Of 
these streams the middle part of the Tees is the longest and 
much the largest. It enters Middle Teesdale from the Upper 
Dale by the Eggleston Gap, with a sharp change in its general 
direction on doing so. It then flows for about six miles in an 
almost straight trench at the foot of the fault-line scarp of 
Marwood Scar, receiving several tributaries from the west and 
none from the east. At Barnard Castle, the Tees bends east- 
ward, and thence flows, along an arc convex to the south, to its 
junction with the Langley Beck through a series of alternating 
gorges and wider terraced valleys. On joining the Langley 
Beck the river resumes its E.S.E. direction, and two or three 
miles lower it leaves the Carboniferous rocks. 
A STUDY IN RIVER DEVELOPMENT. 
This northern west-to-east valley is very similar to the one 
south of the Tees which is occupied by the River Greta and 
the Tutta and Clow Becks. Except for the parts of streams in 
fault-line valleys and in subsequent reaches due to stream 
capture, there are few subsequent, and still fewer obsequent 
1915 Oct. 1. 
