214 YORKSHIRE NATURALISTS’ UNION AT ROKEBY. 
examine the locality during various seasons of the year, many 
interesting additions would no doubt be met with. 
r. Benj. Holgate, F.G.S., presented the report of the Geological 
Section, in the absence of all its officers, and writes as follows :— 
Standing on the ground above Flatt Wood, and near the old and 
celebrated castle the landscape, with the bright sunshine upon it, lay 
beneath. In the far distance were the Stang and Mickle Fell moun- 
tains. Looking nearer, the rounded forms of the hillocks showed 
that they were made of a soft material, while the bright verdure of 
the herbage told us that limestone played an important part in the 
richness and quantity of the grass. 
We stood on what had once been the direct path of an immense 
glacier, which, creeping along the side of Helvelyn, over Shap, and 
passing slowly across the upper reach of the vale of the Eden, and 
over Stainmoor into the Tees valley, spread itself even into the vale 
of Mowbray, carrying with it rocks that it had torn from every place 
that it had passed over. 
Abundant evidence of this was forthcoming. No less than five 
huge blocks of Shap granite were passed on the road side, one of 
which contained not only the large crystals of felspar so characteristic 
of this rock, but also the dark-grey Shap granite attached in the same 
piece. The rivulets which feed the Tees, were each to be found 
between deep and steep banks of the soft clayey residue left by this 
glacier, as it melted and receded up the valley. In some places, 
notably in the Deepdale beck, huge rocks might be seen among the 
debris, looking as if they would block up the stream. 
The party passed over the crag of grit rock upon which the 
castle is built, descending quickly into the bed of the river. 
At the place where the Deepdale beck enters the Tees, and just 
by the bridge, is a bed of very black shale, some six feet in thickness, 
which is sure to contain many fossils, lying as it does immediately 
over an impure limestone, which here forms the bed of the river, and 
which is made up almost entirely of marine animals and shells, with 
small pieces of floated vegetable matter among it. As the river was 
descended, the limestone was seen to become pure and white, and 
composed almost entirely of shells, for we were now on the thick mass 
described by Professor Phillips as the ‘ Main Limestone,’ the upper- 
most member of his Yoredale group. 
The view from Eggleston Bridge was lovely, whether we looked 
up or down the river. Here it has cut its way through the solid 
limestone rock, leaving its sides precipitous and jagged; in some 
places holes have been bored by the action of pebbles moving in a 
circle by the force of the water when in flood. Above the rocks the 
Naturalist, 
